Re: [PATCH v4 0/2] powerpc/512x: add LocalPlus Bus FIFO device driver

[Alexander Popov]

On 27.10.2015 05:22, Vinod Koul wrote:
> On Thu, Oct 22, 2015 at 01:15:03AM +0300, Alexander Popov wrote:
>> On 12.10.2015 00:08, Alexander Popov wrote:
>>> This driver for Freescale MPC512x LocalPlus Bus FIFO (called SCLPC
>>> in the Reference Manual) allows Direct Memory Access transfers
>>> between RAM and peripheral devices on LocalPlus Bus.
>>
>>> Changes in v4:
>>>  - the race condition is fixed;
>>>  - plenty of style fixes are made;
>>>  - devm_* functions and EPROBE_DEFER are used in probe().
>>
>> Hello,
>>
>> I've done my best to fix the issues pointed by Timur Tabi and Vinod Koul.
>> Could I have a feedback please?
> 
> I dont see to have v4 in my list :( Can you please repost

Hello, Vinod

I'm sure I haven't miss your address in the list of the recipients.
Anyway I can repost.

Anatolij Gustschin wrote that he applied v4 with some fix to mpc5xxx/next
some time ago.

So should I repost v4 for everybody? How should I mark the reposted patches?

Best regards,
Alexander
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Re: [PATCH v4 0/2] powerpc/512x: add LocalPlus Bus FIFO device driver

[Alexander Popov]

On 12.10.2015 00:08, Alexander Popov wrote:
> This driver for Freescale MPC512x LocalPlus Bus FIFO (called SCLPC
> in the Reference Manual) allows Direct Memory Access transfers
> between RAM and peripheral devices on LocalPlus Bus.

> Changes in v4:
>  - the race condition is fixed;
>  - plenty of style fixes are made;
>  - devm_* functions and EPROBE_DEFER are used in probe().

Hello,

I've done my best to fix the issues pointed by Timur Tabi and Vinod Koul.
Could I have a feedback please?

Best regards,
Alexander
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[PATCH v4 1/2] powerpc/512x: add LocalPlus Bus FIFO device driver

[Alexander Popov]

This driver for Freescale MPC512x LocalPlus Bus FIFO (called SCLPC
in the Reference Manual) allows Direct Memory Access transfers
between RAM and peripheral devices on LocalPlus Bus.

Signed-off-by: Alexander Popov 
---
 arch/powerpc/configs/mpc512x_defconfig|   1 +
 arch/powerpc/include/asm/mpc5121.h|  59 +++
 arch/powerpc/platforms/512x/Kconfig   |   6 +
 arch/powerpc/platforms/512x/Makefile  |   1 +
 arch/powerpc/platforms/512x/mpc512x_lpbfifo.c | 539 ++
 5 files changed, 606 insertions(+)
 create mode 100644 arch/powerpc/platforms/512x/mpc512x_lpbfifo.c

diff --git a/arch/powerpc/configs/mpc512x_defconfig 
b/arch/powerpc/configs/mpc512x_defconfig
index 59b85cb..d16d6c5 100644
--- a/arch/powerpc/configs/mpc512x_defconfig
+++ b/arch/powerpc/configs/mpc512x_defconfig
@@ -112,6 +112,7 @@ CONFIG_RTC_DRV_M41T80=y
 CONFIG_RTC_DRV_MPC5121=y
 CONFIG_DMADEVICES=y
 CONFIG_MPC512X_DMA=y
+CONFIG_MPC512x_LPBFIFO=y
 CONFIG_EXT2_FS=y
 CONFIG_EXT2_FS_XIP=y
 CONFIG_EXT3_FS=y
diff --git a/arch/powerpc/include/asm/mpc5121.h 
b/arch/powerpc/include/asm/mpc5121.h
index 4a69cd1..deaeb0b 100644
--- a/arch/powerpc/include/asm/mpc5121.h
+++ b/arch/powerpc/include/asm/mpc5121.h
@@ -60,4 +60,63 @@ struct mpc512x_lpc {
 
 int mpc512x_cs_config(unsigned int cs, u32 val);
 
+/*
+ * SCLPC Module (LPB FIFO)
+ */
+struct mpc512x_lpbfifo {
+   u32 pkt_size;   /* SCLPC Packet Size Register */
+   u32 start_addr; /* SCLPC Start Address Register */
+   u32 ctrl;   /* SCLPC Control Register */
+   u32 enable; /* SCLPC Enable Register */
+   u32 reserved1;
+   u32 status; /* SCLPC Status Register */
+   u32 bytes_done; /* SCLPC Bytes Done Register */
+   u32 emb_sc; /* EMB Share Counter Register */
+   u32 emb_pc; /* EMB Pause Control Register */
+   u32 reserved2[7];
+   u32 data_word;  /* LPC RX/TX FIFO Data Word Register */
+   u32 fifo_status;/* LPC RX/TX FIFO Status Register */
+   u32 fifo_ctrl;  /* LPC RX/TX FIFO Control Register */
+   u32 fifo_alarm; /* LPC RX/TX FIFO Alarm Register */
+};
+
+#define MPC512X_SCLPC_START(1 << 31)
+#define MPC512X_SCLPC_CS(x)(((x) & 0x7) << 24)
+#define MPC512X_SCLPC_FLUSH(1 << 17)
+#define MPC512X_SCLPC_READ (1 << 16)
+#define MPC512X_SCLPC_DAI  (1 << 8)
+#define MPC512X_SCLPC_BPT(x)   ((x) & 0x3f)
+#define MPC512X_SCLPC_RESET(1 << 24)
+#define MPC512X_SCLPC_FIFO_RESET   (1 << 16)
+#define MPC512X_SCLPC_ABORT_INT_ENABLE (1 << 9)
+#define MPC512X_SCLPC_NORM_INT_ENABLE  (1 << 8)
+#define MPC512X_SCLPC_ENABLE   (1 << 0)
+#define MPC512X_SCLPC_SUCCESS  (1 << 24)
+#define MPC512X_SCLPC_FIFO_CTRL(x) (((x) & 0x7) << 24)
+#define MPC512X_SCLPC_FIFO_ALARM(x)((x) & 0x3ff)
+
+enum lpb_dev_portsize {
+   LPB_DEV_PORTSIZE_UNDEFINED = 0,
+   LPB_DEV_PORTSIZE_1_BYTE = 1,
+   LPB_DEV_PORTSIZE_2_BYTES = 2,
+   LPB_DEV_PORTSIZE_4_BYTES = 4,
+   LPB_DEV_PORTSIZE_8_BYTES = 8
+};
+
+enum mpc512x_lpbfifo_req_dir {
+   MPC512X_LPBFIFO_REQ_DIR_READ,
+   MPC512X_LPBFIFO_REQ_DIR_WRITE
+};
+
+struct mpc512x_lpbfifo_request {
+   phys_addr_t dev_phys_addr; /* physical address of some device on LPB */
+   void *ram_virt_addr; /* virtual address of some region in RAM */
+   u32 size;
+   enum lpb_dev_portsize portsize;
+   enum mpc512x_lpbfifo_req_dir dir;
+   void (*callback)(struct mpc512x_lpbfifo_request *);
+};
+
+int mpc512x_lpbfifo_submit(struct mpc512x_lpbfifo_request *req);
+
 #endif /* __ASM_POWERPC_MPC5121_H__ */
diff --git a/arch/powerpc/platforms/512x/Kconfig 
b/arch/powerpc/platforms/512x/Kconfig
index 48bf38d..f09016f 100644
--- a/arch/powerpc/platforms/512x/Kconfig
+++ b/arch/powerpc/platforms/512x/Kconfig
@@ -10,6 +10,12 @@ config PPC_MPC512x
select USB_EHCI_BIG_ENDIAN_MMIO if USB_EHCI_HCD
select USB_EHCI_BIG_ENDIAN_DESC if USB_EHCI_HCD
 
+config MPC512x_LPBFIFO
+   tristate "MPC512x LocalPlus Bus FIFO driver"
+   depends on PPC_MPC512x && MPC512X_DMA
+   help
+ Enable support for Freescale MPC512x LocalPlus Bus FIFO (SCLPC).
+
 config MPC5121_ADS
bool "Freescale MPC5121E ADS"
depends on PPC_MPC512x
diff --git a/arch/powerpc/platforms/512x/Makefile 
b/arch/powerpc/platforms/512x/Makefile
index 0169312..f47d422 100644
--- a/arch/powerpc/platforms/512x/Makefile
+++ b/arch/powerpc/platforms/512x/Makefile
@@ -5,4 +5,5 @@ obj-$(CONFIG_COMMON_CLK)+= clock-commonclk.o
 obj-y  += mpc512x_shared.o
 obj-$(CONFIG_MPC5121_ADS)  += mpc5121_ads.o mpc5121_ads_cpld.o
 obj-$(CONFIG_MPC512x_GENERIC)  += mpc512x_generic.o
+obj-$(C

[PATCH v4 2/2] powerpc/512x: add a device tree binding for LocalPlus Bus FIFO

[Alexander Popov]

Add a device tree binding for Freescale MPC512x LocalPlus Bus FIFO and
introduce the document describing that binding.

Signed-off-by: Alexander Popov 
---
 .../bindings/powerpc/fsl/mpc512x_lpbfifo.txt| 21 +
 arch/powerpc/boot/dts/mpc5121.dtsi  | 11 +--
 arch/powerpc/boot/dts/mpc5125twr.dts| 11 ++-
 3 files changed, 40 insertions(+), 3 deletions(-)
 create mode 100644 
Documentation/devicetree/bindings/powerpc/fsl/mpc512x_lpbfifo.txt

diff --git a/Documentation/devicetree/bindings/powerpc/fsl/mpc512x_lpbfifo.txt 
b/Documentation/devicetree/bindings/powerpc/fsl/mpc512x_lpbfifo.txt
new file mode 100644
index 000..b3b392f
--- /dev/null
+++ b/Documentation/devicetree/bindings/powerpc/fsl/mpc512x_lpbfifo.txt
@@ -0,0 +1,21 @@
+Freescale MPC512x LocalPlus Bus FIFO (called SCLPC in the Reference Manual)
+
+Required properties:
+- compatible: should be "fsl,mpc512x-lpbfifo";
+- reg: should contain the offset and length of SCLPC register set;
+- interrupts: should contain the interrupt specifier for SCLPC; syntax of an
+interrupt client node is described in interrupt-controller/interrupts.txt;
+- dmas: should contain the DMA specifier for SCLPC as described at
+dma/dma.txt and dma/mpc512x-dma.txt;
+- dma-names: should be "rx-tx";
+
+Example:
+
+   sclpc@10100 {
+   compatible = "fsl,mpc512x-lpbfifo";
+   reg = <0x10100 0x50>;
+   interrupts = <7 0x8>;
+   dmas = <&dma0 26>;
+   dma-names = "rx-tx";
+   };
+
diff --git a/arch/powerpc/boot/dts/mpc5121.dtsi 
b/arch/powerpc/boot/dts/mpc5121.dtsi
index 7f9d14f..a015e45 100644
--- a/arch/powerpc/boot/dts/mpc5121.dtsi
+++ b/arch/powerpc/boot/dts/mpc5121.dtsi
@@ -77,7 +77,6 @@
#address-cells = <2>;
#size-cells = <1>;
reg = <0x8020 0x40>;
-   interrupts = <7 0x8>;
ranges = <0x0 0x0 0xfc00 0x0400>;
};
 
@@ -329,7 +328,15 @@
/* LocalPlus controller */
lpc@1 {
compatible = "fsl,mpc5121-lpc";
-   reg = <0x1 0x200>;
+   reg = <0x1 0x100>;
+   };
+
+   sclpc@10100 {
+   compatible = "fsl,mpc512x-lpbfifo";
+   reg = <0x10100 0x50>;
+   interrupts = <7 0x8>;
+   dmas = <&dma0 26>;
+   dma-names = "rx-tx";
};
 
pata@10200 {
diff --git a/arch/powerpc/boot/dts/mpc5125twr.dts 
b/arch/powerpc/boot/dts/mpc5125twr.dts
index e4f2974..898eb58 100644
--- a/arch/powerpc/boot/dts/mpc5125twr.dts
+++ b/arch/powerpc/boot/dts/mpc5125twr.dts
@@ -246,6 +246,14 @@
status = "disabled";
};
 
+   sclpc@10100 {
+   compatible = "fsl,mpc512x-lpbfifo";
+   reg = <0x10100 0x50>;
+   interrupts = <7 0x8>;
+   dmas = <&dma0 26>;
+   dma-names = "rx-tx";
+   };
+
// 5125 PSCs are not 52xx or 5121 PSC compatible
// PSC1 uart0 aka ttyPSC0
serial@11100 {
@@ -279,10 +287,11 @@
clock-names = "ipg";
};
 
-   dma@14000 {
+   dma0: dma@14000 {
compatible = "fsl,mpc5121-dma"; // BSP name: 
"mpc512x-dma2"
reg = <0x14000 0x1800>;
interrupts = <65 0x8>;
+   #dma-cells = <1>;
};
};
 };
-- 
1.9.1

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[PATCH v4 0/2] powerpc/512x: add LocalPlus Bus FIFO device driver

[Alexander Popov]

This driver for Freescale MPC512x LocalPlus Bus FIFO (called SCLPC
in the Reference Manual) allows Direct Memory Access transfers
between RAM and peripheral devices on LocalPlus Bus.

Changes in v3:
 - resource usage in probe() is fixed;
 - driver methods are made safe against remove();
 - dma_request_slave_channel() is used to get DMA channel number from
the device tree;
 - chip select number concerned with the DMA transaction is determined
from 'localbus' device tree node information;
 - register set is described as a structure;
 - symbolic names are given to shift counts to keep magic numbers
out of the code;
 - choosing values for LPBFIFO BPT (bytes per transfer) and DMA maxburst
is improved, so DMA transfer size has increased for some cases;
 - device tree binding for LPBFIFO is documented;
 - Kconfig and Makefile are improved;
 - email address "a13xp0p0...@gmail.com" is changed to a more pleasant
alias "alex.po...@linux.com".

Changes in v4:
 - the race condition is fixed;
 - plenty of style fixes are made;
 - devm_* functions and EPROBE_DEFER are used in probe().

Alexander Popov (2):
  powerpc/512x: add LocalPlus Bus FIFO device driver
  powerpc/512x: add a device tree binding for LocalPlus Bus FIFO

 .../bindings/powerpc/fsl/mpc512x_lpbfifo.txt   |  21 +
 arch/powerpc/boot/dts/mpc5121.dtsi |  11 +-
 arch/powerpc/boot/dts/mpc5125twr.dts   |  11 +-
 arch/powerpc/configs/mpc512x_defconfig |   1 +
 arch/powerpc/include/asm/mpc5121.h |  59 +++
 arch/powerpc/platforms/512x/Kconfig|   6 +
 arch/powerpc/platforms/512x/Makefile   |   1 +
 arch/powerpc/platforms/512x/mpc512x_lpbfifo.c  | 539 +
 8 files changed, 646 insertions(+), 3 deletions(-)
 create mode 100644 
Documentation/devicetree/bindings/powerpc/fsl/mpc512x_lpbfifo.txt
 create mode 100644 arch/powerpc/platforms/512x/mpc512x_lpbfifo.c

-- 
1.9.1

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Re: [PATCH v3 3/3] dmaengine: mpc512x: initialize with subsys_initcall()

[Alexander Popov]

On 07.10.2015 17:17, Vinod Koul wrote:
> On Thu, Sep 24, 2015 at 08:28:57PM +0300, Alexander Popov wrote:
>> Initialize Freescale MPC512x DMA driver with subsys_initcall()
>> to allow the depending drivers to call dma_request_slave_channel()
>> during their probe.
> 
> Why can't we use defered probe ? I have been asking people to not move init
> levels and esnure we have right solutions using defered probe

Thanks, Vinod, I'll do it in v4.

Best regards,
Alexander

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Re: [PATCH v3 1/3] powerpc/512x: add LocalPlus Bus FIFO device driver

[Alexander Popov]

On 01.10.2015 20:11, Timur Tabi wrote:
> On 09/30/2015 04:24 PM, Alexander Popov wrote:
>>> Driver code that has to parse #address-cells or #size-cells
>>> is usually wrong.
>>
>> I would not call it "parsing", I just check whether the dts-file is good.
>> Anyway, could you give me a clue how to do better?
> 
> You should use of_n_size_cells() and of_n_addr_cells().

It seems that of_n_size_cells() and of_n_addr_cells() don't work well in
my case. These functions just help to get "#address-cells" and "#size-cells"
from a parent node of a given node.

"sclpc" device tree node is a child of "soc" node (not "localbus" node),
but the driver must use "ranges" property of "localbus" to determine
the chip select number of a client device which ordered the DMA transfer.

It seems that ns2_leds_get_of_pdata() from linux/drivers/leds/leds-ns2.c
or pnv_init_idle_states() from arch/powerpc/platforms/powernv/idle.c do
something similar to get_cs_ranges().
Is it OK?

Best regards,
Alexander
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Re: [PATCH v3 1/3] powerpc/512x: add LocalPlus Bus FIFO device driver

[Alexander Popov]

Hello Timur, thanks again for your review.

On 25.09.2015 04:01, Timur Tabi wrote:
> Alexander Popov wrote:
>> +
>> +for (i = 0; i < lpbfifo.cs_n; i++) {
>> +phys_addr_t cs_start;
>> +phys_addr_t cs_end;
>> +
>> +cs_start = lpbfifo.cs_ranges[i].addr;
>> +cs_end = cs_start + lpbfifo.cs_ranges[i].size - 1;
>> +
>> +if (lpbfifo.req->bus_phys >= cs_start &&
>> +lpbfifo.req->bus_phys + lpbfifo.req->size - 1 <= cs_end) {
>> +cs = lpbfifo.cs_ranges[i].csnum;
>> +break;
>> +}
>> +}
>> +if (i == lpbfifo.cs_n) {
> 
> Can you test for "!cs" here instead?
> 
>> +e = -EFAULT;
>> +goto err_param;
>> +}

Unfortunately no: 0 is a valid value for Chip Select.
Is it OK to leave it like that?

>> +
>> +/* 2. Prepare DMA */
>> +dma_dev = lpbfifo.chan->device;
>> +
>> +sg_init_table(&sg, 1);
>> +if (lpbfifo.req->dir == MPC512X_LPBFIFO_REQ_DIR_WRITE)
>> +dir = DMA_TO_DEVICE;
>> +else
>> +dir = DMA_FROM_DEVICE;
>> +sg_dma_address(&sg) = dma_map_single(dma_dev->dev,
>> +lpbfifo.req->ram_virt, lpbfifo.req->size, dir);
>> +if (dma_mapping_error(dma_dev->dev, sg_dma_address(&sg))) {
>> +e = -EFAULT;
>> +goto err_param;
>> +}
>> +lpbfifo.ram_bus_addr = sg_dma_address(&sg); /* For freeing later */
>> +sg_dma_len(&sg) = lpbfifo.req->size;
> 
> I don't think sg_dma_len() is meant to be used as an lvalue.

I've double-checked and found many cases of such usage of this macro.
It seems that I can't avoid it too.

>> +/*
>> + * The node defined as compatible with 'fsl,mpc5121-localbus'
>> + * should have 2 address cells and 1 size cell.
>> + * One item of its ranges property should consist of:
>> + * - the first address cell which is the chipselect number;
>> + * - the second address cell which is the offset in the chipselect,
>> + *must be zero.
>> + * - CPU address of the beginning of an access window;
>> + * - the only size cell which is the size of an access window.
>> + */
>> +addr_cells_p = of_get_property(lb_node, "#address-cells", NULL);
>> +size_cells_p = of_get_property(lb_node, "#size-cells", NULL);
>> +if (addr_cells_p == NULL || *addr_cells_p != 2 ||
>> +size_cells_p == NULL ||*size_cells_p != 1) {
>> +goto end1;
>> +}
> 
> Is this really necessary?

I'm not sure.

I've found a device tree node compatible with "fsl,mpc5121-localbus"
and I just check the format of "ranges" property before parsing it
because devicetree/bindings/powerpc/fsl/lbc.txt doesn't have details
about it.

Should I blindly assume that this property has 2 address cells and 1 size
cell?

> Can't you use the built-in OF functions for
> parsing ranges? 

I don't see anything to use instead of of_property_count_u32_elems() and
of_property_read_u32_array().

> Driver code that has to parse #address-cells or #size-cells
> is usually wrong.

I would not call it "parsing", I just check whether the dts-file is good.
Anyway, could you give me a clue how to do better?

>> +
>> +proplen = of_property_count_u32_elems(lb_node, "ranges");
>> +if (proplen < 0 || proplen % 4 != 0)
>> +goto end1;
>> +
>> +lpbfifo.cs_n = proplen / 4;
>> +lpbfifo.cs_ranges = kcalloc(lpbfifo.cs_n, sizeof(struct cs_range),
>> +GFP_KERNEL);
>> +if (!lpbfifo.cs_ranges)
>> +goto end1;
>> +
>> +if (of_property_read_u32_array(lb_node, "ranges",
>> +(u32 *)lpbfifo.cs_ranges, proplen) != 0) {
>> +goto end2;
>> +}
>> +
>> +for (i = 0; i < lpbfifo.cs_n; i++) {
>> +if (lpbfifo.cs_ranges[i].base != 0)
>> +goto end2;
>> +}
>> +
>> +res = 0;
>> + end2:
>> +if (res != 0)
>> +kfree(lpbfifo.cs_ranges);
>> + end1:
>> +of_node_put(lb_node);
>> + end0:
>> +return res;
>> +}

Best regards,
Alexander
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Re: [PATCH v3 2/3] powerpc/512x: add a device tree binding for LocalPlus Bus FIFO

[Alexander Popov]

On 28.09.2015 16:26, Timur Tabi wrote:
> Alexander Popov wrote:
>> I've just followed devicetree/bindings/dma/dma.txt...
>> This "rx-tx" doesn't mean much but it could show that LocalPlus Bus FIFO
>> uses a single DMA read-write channel. Should I really drop it?
> 
> Hmmm, I'm not sure.  Is there anything else (besides your driver) that
> parses this device tree node?

No, mpc512x_lpbfifo.c is the only piece of code which is going to use this
device tree node.

> dma.txt says this:
> 
> "The specific strings that can be used are defined in the binding of the
> DMA client device."
> 
> So this looks like it's driver-specific,

Yes.
MPC512x LocalPlus Bus FIFO uses the channel #26 of the DMA controller
both for reading and writing, and other DMA clients use other specific
DMA channels. This channel assignment is fixed in hardware and described
in the Reference Manual.

> but it is a required property.
> I guess you should keep it, but I think you should get a second opinion.

Ok, thanks.

Best regards,
Alexander
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Re: [PATCH v3 1/3] powerpc/512x: add LocalPlus Bus FIFO device driver

[Alexander Popov]

On 28.09.2015 16:18, Timur Tabi wrote:
> Alexander Popov wrote:
>> The only question I have: why calling dma_unmap_single() from within
>> a spinlock is a bad practice?
> 
> I don't know, but usually functions that allocate or free memory cannot be
> called from within a spinlock.  You need to check that.  Since the MPC5121
> is a single-core CPU, you might not notice if you're doing something wrong.

I've double-checked the code and LDD and don't see any reason to avoid
calling dma_unmap_single() from interrupt context and within spinlock.

Please correct me if I'm wrong.
Thanks.

Best regards,
Alexander
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Re: [PATCH v3 2/3] powerpc/512x: add a device tree binding for LocalPlus Bus FIFO

[Alexander Popov]

On 25.09.2015 03:18, Timur Tabi wrote:
> Alexander Popov wrote:
>> +- dma-names: should be "rx-tx";
> 
> Why bother, if it can only be one value?

I've just followed devicetree/bindings/dma/dma.txt...
This "rx-tx" doesn't mean much but it could show that LocalPlus Bus FIFO
uses a single DMA read-write channel. Should I really drop it?

Best regards,
Alexander
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Re: [PATCH v3 3/3] dmaengine: mpc512x: initialize with subsys_initcall()

[Alexander Popov]

On 25.09.2015 03:16, Timur Tabi wrote:
> Alexander Popov wrote:
>> Initialize Freescale MPC512x DMA driver with subsys_initcall()
>> to allow the depending drivers to call dma_request_slave_channel()
>> during their probe.
>>
>> Signed-off-by: Alexander Popov
> 
> Is there any way we can use -EPROBEDEFER instead?

Thanks Timur, I'll try.

Best regards,
Alexander
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Re: [PATCH v3 1/3] powerpc/512x: add LocalPlus Bus FIFO device driver

[Alexander Popov]

Hello, Timur, thanks a lot for your review.
I'll fix all the issues you pointed at and return with v4.

The only question I have: why calling dma_unmap_single() from within
a spinlock is a bad practice?

Best regards,
Alexander
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[PATCH v3 3/3] dmaengine: mpc512x: initialize with subsys_initcall()

[Alexander Popov]

Initialize Freescale MPC512x DMA driver with subsys_initcall()
to allow the depending drivers to call dma_request_slave_channel()
during their probe.

Signed-off-by: Alexander Popov 
---
 drivers/dma/mpc512x_dma.c | 12 +++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/dma/mpc512x_dma.c b/drivers/dma/mpc512x_dma.c
index e6281e7..4f29d7c 100644
--- a/drivers/dma/mpc512x_dma.c
+++ b/drivers/dma/mpc512x_dma.c
@@ -1083,7 +1083,17 @@ static struct platform_driver mpc_dma_driver = {
},
 };
 
-module_platform_driver(mpc_dma_driver);
+static int __init mpc_dma_driver_init(void)
+{
+   return platform_driver_register(&mpc_dma_driver);
+}
+subsys_initcall(mpc_dma_driver_init);
+
+static void __exit mpc_dma_driver_exit(void)
+{
+   platform_driver_unregister(&mpc_dma_driver);
+}
+module_exit(mpc_dma_driver_exit);
 
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Piotr Ziecik ");
-- 
1.9.1

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[PATCH v3 0/3] powerpc/512x: add LocalPlus Bus FIFO device driver

[Alexander Popov]

This driver for Freescale MPC512x LocalPlus Bus FIFO (called SCLPC
in the Reference Manual) allows Direct Memory Access transfers
between RAM and peripheral devices on LocalPlus Bus.

Changes in v3:
 - resource usage in probe() is fixed;
 - driver methods are made safe against remove();
 - dma_request_slave_channel() is used to get DMA channel number from
the device tree;
 - chip select number concerned with the DMA transaction is determined
from 'localbus' device tree node information;
 - register set is described as a structure;
 - symbolic names are given to shift counts to keep magic numbers
out of the code;
 - choosing values for LPBFIFO BPT (bytes per transfer) and DMA maxburst
is improved, so DMA transfer size has increased for some cases;
 - device tree binding for LPBFIFO is documented;
 - Kconfig and Makefile are improved;
 - email address "a13xp0p0...@gmail.com" is changed to a more pleasant
alias "alex.po...@linux.com";

Alexander Popov (3):
  powerpc/512x: add LocalPlus Bus FIFO device driver
  powerpc/512x: add a device tree binding for LocalPlus Bus FIFO
  dmaengine: mpc512x: initialize with subsys_initcall()

 .../bindings/powerpc/fsl/mpc512x_lpbfifo.txt   |  21 +
 arch/powerpc/boot/dts/mpc5121.dtsi |  11 +-
 arch/powerpc/boot/dts/mpc5125twr.dts   |  11 +-
 arch/powerpc/configs/mpc512x_defconfig |   1 +
 arch/powerpc/include/asm/mpc5121.h |  59 +++
 arch/powerpc/platforms/512x/Kconfig|   6 +
 arch/powerpc/platforms/512x/Makefile   |   1 +
 arch/powerpc/platforms/512x/mpc512x_lpbfifo.c  | 560 +
 drivers/dma/mpc512x_dma.c  |  12 +-
 9 files changed, 678 insertions(+), 4 deletions(-)
 create mode 100644 
Documentation/devicetree/bindings/powerpc/fsl/mpc512x_lpbfifo.txt
 create mode 100644 arch/powerpc/platforms/512x/mpc512x_lpbfifo.c

-- 
1.9.1

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[PATCH v3 2/3] powerpc/512x: add a device tree binding for LocalPlus Bus FIFO

[Alexander Popov]

Add a device tree binding for Freescale MPC512x LocalPlus Bus FIFO and
introduce the document describing that binding.

Signed-off-by: Alexander Popov 
---
 .../bindings/powerpc/fsl/mpc512x_lpbfifo.txt| 21 +
 arch/powerpc/boot/dts/mpc5121.dtsi  | 11 +--
 arch/powerpc/boot/dts/mpc5125twr.dts| 11 ++-
 3 files changed, 40 insertions(+), 3 deletions(-)
 create mode 100644 
Documentation/devicetree/bindings/powerpc/fsl/mpc512x_lpbfifo.txt

diff --git a/Documentation/devicetree/bindings/powerpc/fsl/mpc512x_lpbfifo.txt 
b/Documentation/devicetree/bindings/powerpc/fsl/mpc512x_lpbfifo.txt
new file mode 100644
index 000..b3b392f
--- /dev/null
+++ b/Documentation/devicetree/bindings/powerpc/fsl/mpc512x_lpbfifo.txt
@@ -0,0 +1,21 @@
+Freescale MPC512x LocalPlus Bus FIFO (called SCLPC in the Reference Manual)
+
+Required properties:
+- compatible: should be "fsl,mpc512x-lpbfifo";
+- reg: should contain the offset and length of SCLPC register set;
+- interrupts: should contain the interrupt specifier for SCLPC; syntax of an
+interrupt client node is described in interrupt-controller/interrupts.txt;
+- dmas: should contain the DMA specifier for SCLPC as described at
+dma/dma.txt and dma/mpc512x-dma.txt;
+- dma-names: should be "rx-tx";
+
+Example:
+
+   sclpc@10100 {
+   compatible = "fsl,mpc512x-lpbfifo";
+   reg = <0x10100 0x50>;
+   interrupts = <7 0x8>;
+   dmas = <&dma0 26>;
+   dma-names = "rx-tx";
+   };
+
diff --git a/arch/powerpc/boot/dts/mpc5121.dtsi 
b/arch/powerpc/boot/dts/mpc5121.dtsi
index 7f9d14f..a015e45 100644
--- a/arch/powerpc/boot/dts/mpc5121.dtsi
+++ b/arch/powerpc/boot/dts/mpc5121.dtsi
@@ -77,7 +77,6 @@
#address-cells = <2>;
#size-cells = <1>;
reg = <0x8020 0x40>;
-   interrupts = <7 0x8>;
ranges = <0x0 0x0 0xfc00 0x0400>;
};
 
@@ -329,7 +328,15 @@
/* LocalPlus controller */
lpc@1 {
compatible = "fsl,mpc5121-lpc";
-   reg = <0x1 0x200>;
+   reg = <0x1 0x100>;
+   };
+
+   sclpc@10100 {
+   compatible = "fsl,mpc512x-lpbfifo";
+   reg = <0x10100 0x50>;
+   interrupts = <7 0x8>;
+   dmas = <&dma0 26>;
+   dma-names = "rx-tx";
};
 
pata@10200 {
diff --git a/arch/powerpc/boot/dts/mpc5125twr.dts 
b/arch/powerpc/boot/dts/mpc5125twr.dts
index e4f2974..898eb58 100644
--- a/arch/powerpc/boot/dts/mpc5125twr.dts
+++ b/arch/powerpc/boot/dts/mpc5125twr.dts
@@ -246,6 +246,14 @@
status = "disabled";
};
 
+   sclpc@10100 {
+   compatible = "fsl,mpc512x-lpbfifo";
+   reg = <0x10100 0x50>;
+   interrupts = <7 0x8>;
+   dmas = <&dma0 26>;
+   dma-names = "rx-tx";
+   };
+
// 5125 PSCs are not 52xx or 5121 PSC compatible
// PSC1 uart0 aka ttyPSC0
serial@11100 {
@@ -279,10 +287,11 @@
clock-names = "ipg";
};
 
-   dma@14000 {
+   dma0: dma@14000 {
compatible = "fsl,mpc5121-dma"; // BSP name: 
"mpc512x-dma2"
reg = <0x14000 0x1800>;
interrupts = <65 0x8>;
+   #dma-cells = <1>;
};
};
 };
-- 
1.9.1

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[PATCH v3 1/3] powerpc/512x: add LocalPlus Bus FIFO device driver

[Alexander Popov]

This driver for Freescale MPC512x LocalPlus Bus FIFO (called SCLPC
in the Reference Manual) allows Direct Memory Access transfers
between RAM and peripheral devices on LocalPlus Bus.

Signed-off-by: Alexander Popov 
---
 arch/powerpc/configs/mpc512x_defconfig|   1 +
 arch/powerpc/include/asm/mpc5121.h|  59 +++
 arch/powerpc/platforms/512x/Kconfig   |   6 +
 arch/powerpc/platforms/512x/Makefile  |   1 +
 arch/powerpc/platforms/512x/mpc512x_lpbfifo.c | 560 ++
 5 files changed, 627 insertions(+)
 create mode 100644 arch/powerpc/platforms/512x/mpc512x_lpbfifo.c

diff --git a/arch/powerpc/configs/mpc512x_defconfig 
b/arch/powerpc/configs/mpc512x_defconfig
index 59b85cb..d16d6c5 100644
--- a/arch/powerpc/configs/mpc512x_defconfig
+++ b/arch/powerpc/configs/mpc512x_defconfig
@@ -112,6 +112,7 @@ CONFIG_RTC_DRV_M41T80=y
 CONFIG_RTC_DRV_MPC5121=y
 CONFIG_DMADEVICES=y
 CONFIG_MPC512X_DMA=y
+CONFIG_MPC512x_LPBFIFO=y
 CONFIG_EXT2_FS=y
 CONFIG_EXT2_FS_XIP=y
 CONFIG_EXT3_FS=y
diff --git a/arch/powerpc/include/asm/mpc5121.h 
b/arch/powerpc/include/asm/mpc5121.h
index 4a69cd1..a6e8225 100644
--- a/arch/powerpc/include/asm/mpc5121.h
+++ b/arch/powerpc/include/asm/mpc5121.h
@@ -60,4 +60,63 @@ struct mpc512x_lpc {
 
 int mpc512x_cs_config(unsigned int cs, u32 val);
 
+/*
+ * SCLPC Module (LPB FIFO)
+ */
+struct mpc512x_lpbfifo {
+   u32 pkt_size;   /* SCLPC Packet Size Register */
+   u32 start_addr; /* SCLPC Start Address Register */
+   u32 ctrl;   /* SCLPC Control Register */
+   u32 enable; /* SCLPC Enable Register */
+   u32 reserved1;
+   u32 status; /* SCLPC Status Register */
+   u32 bytes_done; /* SCLPC Bytes Done Register */
+   u32 emb_sc; /* EMB Share Counter Register */
+   u32 emb_pc; /* EMB Pause Control Register */
+   u32 reserved2[7];
+   u32 data_word;  /* LPC RX/TX FIFO Data Word Register */
+   u32 fifo_status;/* LPC RX/TX FIFO Status Register */
+   u32 fifo_ctrl;  /* LPC RX/TX FIFO Control Register */
+   u32 fifo_alarm; /* LPC RX/TX FIFO Alarm Register */
+};
+
+#define MPC512X_SCLPC_START(1 << 31)
+#define MPC512X_SCLPC_CS(x)(((x) & 0x7) << 24)
+#define MPC512X_SCLPC_FLUSH(1 << 17)
+#define MPC512X_SCLPC_READ (1 << 16)
+#define MPC512X_SCLPC_DAI  (1 << 8)
+#define MPC512X_SCLPC_BPT(x)   ((x) & 0x3f)
+#define MPC512X_SCLPC_RESET(1 << 24)
+#define MPC512X_SCLPC_FIFO_RESET   (1 << 16)
+#define MPC512X_SCLPC_ABORT_INT_ENABLE (1 << 9)
+#define MPC512X_SCLPC_NORM_INT_ENABLE  (1 << 8)
+#define MPC512X_SCLPC_ENABLE   (1 << 0)
+#define MPC512X_SCLPC_SUCCESS  (1 << 24)
+#define MPC512X_SCLPC_FIFO_CTRL(x) (((x) & 0x7) << 24)
+#define MPC512X_SCLPC_FIFO_ALARM(x)((x) & 0x3ff)
+
+enum lpb_dev_portsize {
+   LPB_DEV_PORTSIZE_UNDEFINED = 0,
+   LPB_DEV_PORTSIZE_1_BYTE = 1,
+   LPB_DEV_PORTSIZE_2_BYTES = 2,
+   LPB_DEV_PORTSIZE_4_BYTES = 4,
+   LPB_DEV_PORTSIZE_8_BYTES = 8
+};
+
+enum mpc512x_lpbfifo_req_dir {
+   MPC512X_LPBFIFO_REQ_DIR_READ,
+   MPC512X_LPBFIFO_REQ_DIR_WRITE
+};
+
+struct mpc512x_lpbfifo_request {
+   phys_addr_t bus_phys;   /* physical address of some device on LPB */
+   void *ram_virt; /* virtual address of some region in RAM */
+   u32 size;
+   enum lpb_dev_portsize portsize;
+   enum mpc512x_lpbfifo_req_dir dir;
+   void (*callback)(struct mpc512x_lpbfifo_request *);
+};
+
+int mpc512x_lpbfifo_submit(struct mpc512x_lpbfifo_request *req);
+
 #endif /* __ASM_POWERPC_MPC5121_H__ */
diff --git a/arch/powerpc/platforms/512x/Kconfig 
b/arch/powerpc/platforms/512x/Kconfig
index 48bf38d..f09016f 100644
--- a/arch/powerpc/platforms/512x/Kconfig
+++ b/arch/powerpc/platforms/512x/Kconfig
@@ -10,6 +10,12 @@ config PPC_MPC512x
select USB_EHCI_BIG_ENDIAN_MMIO if USB_EHCI_HCD
select USB_EHCI_BIG_ENDIAN_DESC if USB_EHCI_HCD
 
+config MPC512x_LPBFIFO
+   tristate "MPC512x LocalPlus Bus FIFO driver"
+   depends on PPC_MPC512x && MPC512X_DMA
+   help
+ Enable support for Freescale MPC512x LocalPlus Bus FIFO (SCLPC).
+
 config MPC5121_ADS
bool "Freescale MPC5121E ADS"
depends on PPC_MPC512x
diff --git a/arch/powerpc/platforms/512x/Makefile 
b/arch/powerpc/platforms/512x/Makefile
index 0169312..f47d422 100644
--- a/arch/powerpc/platforms/512x/Makefile
+++ b/arch/powerpc/platforms/512x/Makefile
@@ -5,4 +5,5 @@ obj-$(CONFIG_COMMON_CLK)+= clock-commonclk.o
 obj-y  += mpc512x_shared.o
 obj-$(CONFIG_MPC5121_ADS)  += mpc5121_ads.o mpc5121_ads_cpld.o
 obj-$(CONFIG_MPC512x_GENERIC)  += mpc512x_generic.o
+obj-$(C

Re: [PATCH v3 0/3] dmaengine: mpc512x: add device tree binding document and DMA channel lookup

[Alexander Popov]

Hello!

2014-06-25 14:52 GMT+04:00 Alexander Popov :
> This patch series introduces a device tree binding document for
> the MPC512x DMA controller and adds device tree based DMA channel lookup
> for it.
>
> This version contains the improved device tree binding document:
> #dma-cells is made a required property, as it must be according
> dma/dma.txt document.

Could I have a feedback, please?
Thanks!

> Alexander Popov (3):
>   dmaengine: mpc512x: add device tree binding document
>   dmaengine: of: add common xlate function for matching by channel id
>   dmaengine: mpc512x: register for device tree channel lookup
>
>  .../devicetree/bindings/dma/mpc512x-dma.txt| 29 ++
>  arch/powerpc/boot/dts/mpc5121.dtsi |  1 +
>  drivers/dma/mpc512x_dma.c  | 13 +++-
>  drivers/dma/of-dma.c   | 35 
> ++
>  include/linux/of_dma.h |  4 +++
>  5 files changed, 81 insertions(+), 1 deletion(-)
>  create mode 100644 Documentation/devicetree/bindings/dma/mpc512x-dma.txt
>
> --
> 1.8.4.2
>
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[PATCH v3 0/3] dmaengine: mpc512x: add device tree binding document and DMA channel lookup

[Alexander Popov]

This patch series introduces a device tree binding document for
the MPC512x DMA controller and adds device tree based DMA channel lookup
for it.

This version contains the improved device tree binding document:
#dma-cells is made a required property, as it must be according
dma/dma.txt document.

Alexander Popov (3):
  dmaengine: mpc512x: add device tree binding document
  dmaengine: of: add common xlate function for matching by channel id
  dmaengine: mpc512x: register for device tree channel lookup

 .../devicetree/bindings/dma/mpc512x-dma.txt| 29 ++
 arch/powerpc/boot/dts/mpc5121.dtsi |  1 +
 drivers/dma/mpc512x_dma.c  | 13 +++-
 drivers/dma/of-dma.c   | 35 ++
 include/linux/of_dma.h |  4 +++
 5 files changed, 81 insertions(+), 1 deletion(-)
 create mode 100644 Documentation/devicetree/bindings/dma/mpc512x-dma.txt

-- 
1.8.4.2

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[PATCH v3 2/3] dmaengine: of: add common xlate function for matching by channel id

[Alexander Popov]

This patch adds a new common OF dma xlate callback function which will match a
channel by it's id. The binding expects one integer argument which it will use 
to
lookup the channel by the id.

Unlike of_dma_simple_xlate this function is able to handle a system with
multiple DMA controllers. When registering the of dma provider with
of_dma_controller_register a pointer to the dma_device struct which is
associated with the dt node needs to passed as the data parameter.
New function will use this pointer to match only channels which belong to the
specified DMA controller.

Signed-off-by: Alexander Popov 
---
 drivers/dma/of-dma.c   | 35 +++
 include/linux/of_dma.h |  4 
 2 files changed, 39 insertions(+)

diff --git a/drivers/dma/of-dma.c b/drivers/dma/of-dma.c
index e8fe9dc..d5fbeaa 100644
--- a/drivers/dma/of-dma.c
+++ b/drivers/dma/of-dma.c
@@ -218,3 +218,38 @@ struct dma_chan *of_dma_simple_xlate(struct 
of_phandle_args *dma_spec,
&dma_spec->args[0]);
 }
 EXPORT_SYMBOL_GPL(of_dma_simple_xlate);
+
+/**
+ * of_dma_xlate_by_chan_id - Translate dt property to DMA channel by channel id
+ * @dma_spec:  pointer to DMA specifier as found in the device tree
+ * @of_dma:pointer to DMA controller data
+ *
+ * This function can be used as the of xlate callback for DMA driver which 
wants
+ * to match the channel based on the channel id. When using this xlate function
+ * the #dma-cells propety of the DMA controller dt node needs to be set to 1.
+ * The data parameter of of_dma_controller_register must be a pointer to the
+ * dma_device struct the function should match upon.
+ *
+ * Returns pointer to appropriate dma channel on success or NULL on error.
+ */
+struct dma_chan *of_dma_xlate_by_chan_id(struct of_phandle_args *dma_spec,
+struct of_dma *ofdma)
+{
+   struct dma_device *dev = ofdma->of_dma_data;
+   struct dma_chan *chan, *candidate = NULL;
+
+   if (!dev || dma_spec->args_count != 1)
+   return NULL;
+
+   list_for_each_entry(chan, &dev->channels, device_node)
+   if (chan->chan_id == dma_spec->args[0]) {
+   candidate = chan;
+   break;
+   }
+
+   if (!candidate)
+   return NULL;
+
+   return dma_get_slave_channel(candidate);
+}
+EXPORT_SYMBOL_GPL(of_dma_xlate_by_chan_id);
diff --git a/include/linux/of_dma.h b/include/linux/of_dma.h
index ae36298..56bc026 100644
--- a/include/linux/of_dma.h
+++ b/include/linux/of_dma.h
@@ -41,6 +41,8 @@ extern struct dma_chan *of_dma_request_slave_channel(struct 
device_node *np,
 const char *name);
 extern struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_spec,
struct of_dma *ofdma);
+extern struct dma_chan *of_dma_xlate_by_chan_id(struct of_phandle_args 
*dma_spec,
+   struct of_dma *ofdma);
 #else
 static inline int of_dma_controller_register(struct device_node *np,
struct dma_chan *(*of_dma_xlate)
@@ -66,6 +68,8 @@ static inline struct dma_chan *of_dma_simple_xlate(struct 
of_phandle_args *dma_s
return NULL;
 }
 
+#define of_dma_xlate_by_chan_id NULL
+
 #endif
 
 #endif /* __LINUX_OF_DMA_H */
-- 
1.8.4.2

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[PATCH v3 3/3] dmaengine: mpc512x: register for device tree channel lookup

[Alexander Popov]

Register the controller for device tree based lookup of DMA channels
(non-fatal for backwards compatibility with older device trees) and
provide the '#dma-cells' property in the shared mpc5121.dtsi file

Signed-off-by: Alexander Popov 
---
 arch/powerpc/boot/dts/mpc5121.dtsi |  1 +
 drivers/dma/mpc512x_dma.c  | 13 -
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/boot/dts/mpc5121.dtsi 
b/arch/powerpc/boot/dts/mpc5121.dtsi
index 2c0e155..7f9d14f 100644
--- a/arch/powerpc/boot/dts/mpc5121.dtsi
+++ b/arch/powerpc/boot/dts/mpc5121.dtsi
@@ -498,6 +498,7 @@
compatible = "fsl,mpc5121-dma";
reg = <0x14000 0x1800>;
interrupts = <65 0x8>;
+   #dma-cells = <1>;
};
};
 
diff --git a/drivers/dma/mpc512x_dma.c b/drivers/dma/mpc512x_dma.c
index 2ad4373..881db2b 100644
--- a/drivers/dma/mpc512x_dma.c
+++ b/drivers/dma/mpc512x_dma.c
@@ -53,6 +53,7 @@
 #include 
 #include 
 #include 
+#include 
 #include 
 
 #include 
@@ -1036,7 +1037,15 @@ static int mpc_dma_probe(struct platform_device *op)
if (retval)
goto err_free2;
 
-   return retval;
+   /* Register with OF helpers for DMA lookups (nonfatal) */
+   if (dev->of_node) {
+   retval = of_dma_controller_register(dev->of_node,
+   of_dma_xlate_by_chan_id, mdma);
+   if (retval)
+   dev_warn(dev, "Could not register for OF lookup\n");
+   }
+
+   return 0;
 
 err_free2:
if (mdma->is_mpc8308)
@@ -1057,6 +1066,8 @@ static int mpc_dma_remove(struct platform_device *op)
struct device *dev = &op->dev;
struct mpc_dma *mdma = dev_get_drvdata(dev);
 
+   if (dev->of_node)
+   of_dma_controller_free(dev->of_node);
dma_async_device_unregister(&mdma->dma);
if (mdma->is_mpc8308) {
free_irq(mdma->irq2, mdma);
-- 
1.8.4.2

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[PATCH v3 1/3] dmaengine: mpc512x: add device tree binding document

[Alexander Popov]

Introduce a device tree binding document for the MPC512x DMA controller

Signed-off-by: Alexander Popov 
---
 .../devicetree/bindings/dma/mpc512x-dma.txt| 29 ++
 1 file changed, 29 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/dma/mpc512x-dma.txt

diff --git a/Documentation/devicetree/bindings/dma/mpc512x-dma.txt 
b/Documentation/devicetree/bindings/dma/mpc512x-dma.txt
new file mode 100644
index 000..a6511df
--- /dev/null
+++ b/Documentation/devicetree/bindings/dma/mpc512x-dma.txt
@@ -0,0 +1,29 @@
+* Freescale MPC512x and MPC8308 DMA Controller
+
+The DMA controller in Freescale MPC512x and MPC8308 SoCs can move
+blocks of memory contents between memory and peripherals or
+from memory to memory.
+
+Refer to "Generic DMA Controller and DMA request bindings" in
+the dma/dma.txt file for a more detailed description of binding.
+
+Required properties:
+- compatible: should be "fsl,mpc5121-dma" or "fsl,mpc8308-dma";
+- reg: should contain the DMA controller registers location and length;
+- interrupt for the DMA controller: syntax of interrupt client node
+   is described in interrupt-controller/interrupts.txt file.
+- #dma-cells: the length of the DMA specifier, must be <1>.
+   Each channel of this DMA controller has a peripheral request line,
+   the assignment is fixed in hardware. This one cell
+   in dmas property of a client device represents the channel number.
+
+Example:
+
+   dma0: dma@14000 {
+   compatible = "fsl,mpc5121-dma";
+   reg = <0x14000 0x1800>;
+   interrupts = <65 0x8>;
+   #dma-cells = <1>;
+   };
+
+DMA clients must use the format described in dma/dma.txt file.
-- 
1.8.4.2

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Re: [PATCH v2 1/3] dmaengine: mpc512x: add device tree binding document

[Alexander Popov]

2014-06-18 18:56 GMT+04:00 Alexander Popov :
> 2014-06-18 17:37 GMT+04:00 Mark Rutland :
>> On Wed, Jun 18, 2014 at 11:48:10AM +0100, Alexander Popov wrote:
>>> Introduce a device tree binding document for the MPC512x DMA controller
>>> +Optional properties:
>>> +- #dma-cells: the length of the DMA specifier, must be <1>.
>>> + Each channel of this DMA controller has a peripheral request line,
>>> + the assignment is fixed in hardware. This one cell
>>> + in dmas property of a client device represents the channel number.
>>
>> Surely this is required to be able to refer to DMA channels on the
>> device?
>
> Excuse me, I didn't understand your question.
> Do you inquire about the reason of making #dma-cells an optional property?
> It's optional because device tree based lookup support is made
> optional (part 3/3).

Mark, did I answer your question?
Should I fix anything in this patch series?

Hope for the reply.
Alexander
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Re: [PATCH v2 1/3] dmaengine: mpc512x: add device tree binding document

[Alexander Popov]

Hello Mark, thanks for your reply!

2014-06-18 17:37 GMT+04:00 Mark Rutland :
> On Wed, Jun 18, 2014 at 11:48:10AM +0100, Alexander Popov wrote:
>> Introduce a device tree binding document for the MPC512x DMA controller
>>
>> Signed-off-by: Alexander Popov 
>> ---
>>  .../devicetree/bindings/dma/mpc512x-dma.txt| 31 
>> ++
>>  1 file changed, 31 insertions(+)
>>  create mode 100644 Documentation/devicetree/bindings/dma/mpc512x-dma.txt
>>
>> diff --git a/Documentation/devicetree/bindings/dma/mpc512x-dma.txt 
>> b/Documentation/devicetree/bindings/dma/mpc512x-dma.txt
>> new file mode 100644
>> index 000..95e2ca0
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/dma/mpc512x-dma.txt
>> @@ -0,0 +1,31 @@
>> +* Freescale MPC512x and MPC8308 DMA Controller
>> +
>> +The DMA controller in Freescale MPC512x and MPC8308 SoCs can move
>> +blocks of memory contents between memory and peripherals or
>> +from memory to memory.
>> +
>> +Refer to "Generic DMA Controller and DMA request bindings" in
>> +the dma/dma.txt file for a more detailed description of binding.
>> +
>> +Required properties:
>> +- compatible: should be "fsl,mpc5121-dma" or "fsl,mpc8308-dma";
>> +- reg: should contain the DMA controller registers location and length;
>> +- interrupt for the DMA controller: syntax of interrupt client node
>> + is described in interrupt-controller/interrupts.txt file.
>> +
>> +Optional properties:
>> +- #dma-cells: the length of the DMA specifier, must be <1>.
>> + Each channel of this DMA controller has a peripheral request line,
>> + the assignment is fixed in hardware. This one cell
>> + in dmas property of a client device represents the channel number.
>
> Surely this is required to be able to refer to DMA channels on the
> device?

Excuse me, I didn't understand your question.
Do you inquire about the reason of making #dma-cells an optional property?
It's optional because device tree based lookup support is made
optional (part 3/3).

Best regards,
Alexander
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[PATCH v2 2/3] dmaengine: of: add common xlate function for matching by channel id

[Alexander Popov]

This patch adds a new common OF dma xlate callback function which will match a
channel by it's id. The binding expects one integer argument which it will use 
to
lookup the channel by the id.

Unlike of_dma_simple_xlate this function is able to handle a system with
multiple DMA controllers. When registering the of dma provider with
of_dma_controller_register a pointer to the dma_device struct which is
associated with the dt node needs to passed as the data parameter.
New function will use this pointer to match only channels which belong to the
specified DMA controller.

Signed-off-by: Alexander Popov 
---
 drivers/dma/of-dma.c   | 35 +++
 include/linux/of_dma.h |  4 
 2 files changed, 39 insertions(+)

diff --git a/drivers/dma/of-dma.c b/drivers/dma/of-dma.c
index e8fe9dc..d5fbeaa 100644
--- a/drivers/dma/of-dma.c
+++ b/drivers/dma/of-dma.c
@@ -218,3 +218,38 @@ struct dma_chan *of_dma_simple_xlate(struct 
of_phandle_args *dma_spec,
&dma_spec->args[0]);
 }
 EXPORT_SYMBOL_GPL(of_dma_simple_xlate);
+
+/**
+ * of_dma_xlate_by_chan_id - Translate dt property to DMA channel by channel id
+ * @dma_spec:  pointer to DMA specifier as found in the device tree
+ * @of_dma:pointer to DMA controller data
+ *
+ * This function can be used as the of xlate callback for DMA driver which 
wants
+ * to match the channel based on the channel id. When using this xlate function
+ * the #dma-cells propety of the DMA controller dt node needs to be set to 1.
+ * The data parameter of of_dma_controller_register must be a pointer to the
+ * dma_device struct the function should match upon.
+ *
+ * Returns pointer to appropriate dma channel on success or NULL on error.
+ */
+struct dma_chan *of_dma_xlate_by_chan_id(struct of_phandle_args *dma_spec,
+struct of_dma *ofdma)
+{
+   struct dma_device *dev = ofdma->of_dma_data;
+   struct dma_chan *chan, *candidate = NULL;
+
+   if (!dev || dma_spec->args_count != 1)
+   return NULL;
+
+   list_for_each_entry(chan, &dev->channels, device_node)
+   if (chan->chan_id == dma_spec->args[0]) {
+   candidate = chan;
+   break;
+   }
+
+   if (!candidate)
+   return NULL;
+
+   return dma_get_slave_channel(candidate);
+}
+EXPORT_SYMBOL_GPL(of_dma_xlate_by_chan_id);
diff --git a/include/linux/of_dma.h b/include/linux/of_dma.h
index ae36298..56bc026 100644
--- a/include/linux/of_dma.h
+++ b/include/linux/of_dma.h
@@ -41,6 +41,8 @@ extern struct dma_chan *of_dma_request_slave_channel(struct 
device_node *np,
 const char *name);
 extern struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_spec,
struct of_dma *ofdma);
+extern struct dma_chan *of_dma_xlate_by_chan_id(struct of_phandle_args 
*dma_spec,
+   struct of_dma *ofdma);
 #else
 static inline int of_dma_controller_register(struct device_node *np,
struct dma_chan *(*of_dma_xlate)
@@ -66,6 +68,8 @@ static inline struct dma_chan *of_dma_simple_xlate(struct 
of_phandle_args *dma_s
return NULL;
 }
 
+#define of_dma_xlate_by_chan_id NULL
+
 #endif
 
 #endif /* __LINUX_OF_DMA_H */
-- 
1.8.4.2

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[PATCH v2 1/3] dmaengine: mpc512x: add device tree binding document

[Alexander Popov]

Introduce a device tree binding document for the MPC512x DMA controller

Signed-off-by: Alexander Popov 
---
 .../devicetree/bindings/dma/mpc512x-dma.txt| 31 ++
 1 file changed, 31 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/dma/mpc512x-dma.txt

diff --git a/Documentation/devicetree/bindings/dma/mpc512x-dma.txt 
b/Documentation/devicetree/bindings/dma/mpc512x-dma.txt
new file mode 100644
index 000..95e2ca0
--- /dev/null
+++ b/Documentation/devicetree/bindings/dma/mpc512x-dma.txt
@@ -0,0 +1,31 @@
+* Freescale MPC512x and MPC8308 DMA Controller
+
+The DMA controller in Freescale MPC512x and MPC8308 SoCs can move
+blocks of memory contents between memory and peripherals or
+from memory to memory.
+
+Refer to "Generic DMA Controller and DMA request bindings" in
+the dma/dma.txt file for a more detailed description of binding.
+
+Required properties:
+- compatible: should be "fsl,mpc5121-dma" or "fsl,mpc8308-dma";
+- reg: should contain the DMA controller registers location and length;
+- interrupt for the DMA controller: syntax of interrupt client node
+   is described in interrupt-controller/interrupts.txt file.
+
+Optional properties:
+- #dma-cells: the length of the DMA specifier, must be <1>.
+   Each channel of this DMA controller has a peripheral request line,
+   the assignment is fixed in hardware. This one cell
+   in dmas property of a client device represents the channel number.
+
+Example:
+
+   dma0: dma@14000 {
+   compatible = "fsl,mpc5121-dma";
+   reg = <0x14000 0x1800>;
+   interrupts = <65 0x8>;
+   #dma-cells = <1>;
+   };
+
+DMA clients must use the format described in dma/dma.txt file.
-- 
1.8.4.2

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[PATCH v2 0/3] dmaengine: mpc512x: add device tree binding document and DMA channel lookup

[Alexander Popov]

This patch series introduces a device tree binding document for
the MPC512x DMA controller and adds device tree based DMA channel lookup
for it.

This version has improved device tree binding document.

Alexander Popov (3):
  dmaengine: mpc512x: add device tree binding document
  dmaengine: of: add common xlate function for matching by channel id
  dmaengine: mpc512x: register for device tree channel lookup

 .../devicetree/bindings/dma/mpc512x-dma.txt| 31 +++
 arch/powerpc/boot/dts/mpc5121.dtsi |  1 +
 drivers/dma/mpc512x_dma.c  | 13 +++-
 drivers/dma/of-dma.c   | 35 ++
 include/linux/of_dma.h |  4 +++
 5 files changed, 83 insertions(+), 1 deletion(-)
 create mode 100644 Documentation/devicetree/bindings/dma/mpc512x-dma.txt

-- 
1.8.4.2

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[PATCH v2 3/3] dmaengine: mpc512x: register for device tree channel lookup

[Alexander Popov]

Register the controller for device tree based lookup of DMA channels
(non-fatal for backwards compatibility with older device trees) and
provide the '#dma-cells' property in the shared mpc5121.dtsi file

Signed-off-by: Alexander Popov 
---
 arch/powerpc/boot/dts/mpc5121.dtsi |  1 +
 drivers/dma/mpc512x_dma.c  | 13 -
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/boot/dts/mpc5121.dtsi 
b/arch/powerpc/boot/dts/mpc5121.dtsi
index 2c0e155..7f9d14f 100644
--- a/arch/powerpc/boot/dts/mpc5121.dtsi
+++ b/arch/powerpc/boot/dts/mpc5121.dtsi
@@ -498,6 +498,7 @@
compatible = "fsl,mpc5121-dma";
reg = <0x14000 0x1800>;
interrupts = <65 0x8>;
+   #dma-cells = <1>;
};
};
 
diff --git a/drivers/dma/mpc512x_dma.c b/drivers/dma/mpc512x_dma.c
index 2ad4373..881db2b 100644
--- a/drivers/dma/mpc512x_dma.c
+++ b/drivers/dma/mpc512x_dma.c
@@ -53,6 +53,7 @@
 #include 
 #include 
 #include 
+#include 
 #include 
 
 #include 
@@ -1036,7 +1037,15 @@ static int mpc_dma_probe(struct platform_device *op)
if (retval)
goto err_free2;
 
-   return retval;
+   /* Register with OF helpers for DMA lookups (nonfatal) */
+   if (dev->of_node) {
+   retval = of_dma_controller_register(dev->of_node,
+   of_dma_xlate_by_chan_id, mdma);
+   if (retval)
+   dev_warn(dev, "Could not register for OF lookup\n");
+   }
+
+   return 0;
 
 err_free2:
if (mdma->is_mpc8308)
@@ -1057,6 +1066,8 @@ static int mpc_dma_remove(struct platform_device *op)
struct device *dev = &op->dev;
struct mpc_dma *mdma = dev_get_drvdata(dev);
 
+   if (dev->of_node)
+   of_dma_controller_free(dev->of_node);
dma_async_device_unregister(&mdma->dma);
if (mdma->is_mpc8308) {
free_irq(mdma->irq2, mdma);
-- 
1.8.4.2

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Re: [PATCH 0/3] dmaengine: mpc512x: add device tree binding document and DMA channel lookup

[Alexander Popov]

2014-05-24 13:33 GMT+04:00 Alexander Popov :
> This patch series introduces a device tree binding document for
> the MPC512x DMA controller and adds device tree based DMA channel lookup
> for it.

Hello, excuse me, could I have a feedback?
Should I fix anything?

Thanks a lot!
Alexander

> Alexander Popov (3):
>   dmaengine: mpc512x: add device tree binding document
>   dmaengine: of: add common xlate function for matching by channel id
>   dmaengine: mpc512x: register for device tree channel lookup
>
>  .../devicetree/bindings/dma/mpc512x-dma.txt| 40 
> ++
>  arch/powerpc/boot/dts/mpc5121.dtsi |  1 +
>  drivers/dma/mpc512x_dma.c  | 13 ++-
>  drivers/dma/of-dma.c   | 35 +++
>  include/linux/of_dma.h |  4 +++
>  5 files changed, 92 insertions(+), 1 deletion(-)
>  create mode 100644 Documentation/devicetree/bindings/dma/mpc512x-dma.txt
>
> --
> 1.8.4.2
>
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[PATCH 1/3] dmaengine: mpc512x: add device tree binding document

[Alexander Popov]

Introduce a device tree binding document for the MPC512x DMA controller

Signed-off-by: Alexander Popov 
---
 .../devicetree/bindings/dma/mpc512x-dma.txt| 40 ++
 1 file changed, 40 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/dma/mpc512x-dma.txt

diff --git a/Documentation/devicetree/bindings/dma/mpc512x-dma.txt 
b/Documentation/devicetree/bindings/dma/mpc512x-dma.txt
new file mode 100644
index 000..b1cbc3f
--- /dev/null
+++ b/Documentation/devicetree/bindings/dma/mpc512x-dma.txt
@@ -0,0 +1,40 @@
+* Freescale MPC512x and MPC8308 DMA Controller
+
+The DMA controller in Freescale MPC512x and MPC8308 SoCs can move
+blocks of memory contents between memory and peripherals or
+from memory to memory.
+
+Refer to "Generic DMA Controller and DMA request bindings" in
+the dma/dma.txt file for a more detailed description of binding.
+
+Required properties:
+- compatible: Should be "fsl,mpc5121-dma" or "fsl,mpc8308-dma"
+- reg: Address and size of the DMA controller's register set
+- Interrupt for the DMA controller. Syntax of interrupt client node
+   is described in interrupt-controller/interrupts.txt
+
+Optional properties:
+- #dma-cells: The length of the DMA specifier, must be <1>.
+   Each channel of this DMA controller has a peripheral request line,
+   this assignment is fixed in hardware. The cell in dmas property
+   of a client device represents the channel number
+
+Example:
+
+   dma0: dma@14000 {
+   compatible = "fsl,mpc5121-dma";
+   reg = <0x14000 0x1800>;
+   interrupts = <65 0x8>;
+   #dma-cells = <1>;
+   };
+
+DMA clients must use the format described in dma/dma.txt
+
+Example:
+
+   sdhc@1500 {
+   compatible = "fsl,mpc5121-sdhc";
+   /* ... */
+   dmas = <&dma0 30>;
+   dma-names = "rx-tx";
+   };
-- 
1.8.4.2

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[PATCH 3/3] dmaengine: mpc512x: register for device tree channel lookup

[Alexander Popov]

Register the controller for device tree based lookup of DMA channels
(non-fatal for backwards compatibility with older device trees) and
provide the '#dma-cells' property in the shared mpc5121.dtsi file

Signed-off-by: Alexander Popov 
---
 arch/powerpc/boot/dts/mpc5121.dtsi |  1 +
 drivers/dma/mpc512x_dma.c  | 13 -
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/boot/dts/mpc5121.dtsi 
b/arch/powerpc/boot/dts/mpc5121.dtsi
index 2c0e155..7f9d14f 100644
--- a/arch/powerpc/boot/dts/mpc5121.dtsi
+++ b/arch/powerpc/boot/dts/mpc5121.dtsi
@@ -498,6 +498,7 @@
compatible = "fsl,mpc5121-dma";
reg = <0x14000 0x1800>;
interrupts = <65 0x8>;
+   #dma-cells = <1>;
};
};
 
diff --git a/drivers/dma/mpc512x_dma.c b/drivers/dma/mpc512x_dma.c
index 2ad4373..881db2b 100644
--- a/drivers/dma/mpc512x_dma.c
+++ b/drivers/dma/mpc512x_dma.c
@@ -53,6 +53,7 @@
 #include 
 #include 
 #include 
+#include 
 #include 
 
 #include 
@@ -1036,7 +1037,15 @@ static int mpc_dma_probe(struct platform_device *op)
if (retval)
goto err_free2;
 
-   return retval;
+   /* Register with OF helpers for DMA lookups (nonfatal) */
+   if (dev->of_node) {
+   retval = of_dma_controller_register(dev->of_node,
+   of_dma_xlate_by_chan_id, mdma);
+   if (retval)
+   dev_warn(dev, "Could not register for OF lookup\n");
+   }
+
+   return 0;
 
 err_free2:
if (mdma->is_mpc8308)
@@ -1057,6 +1066,8 @@ static int mpc_dma_remove(struct platform_device *op)
struct device *dev = &op->dev;
struct mpc_dma *mdma = dev_get_drvdata(dev);
 
+   if (dev->of_node)
+   of_dma_controller_free(dev->of_node);
dma_async_device_unregister(&mdma->dma);
if (mdma->is_mpc8308) {
free_irq(mdma->irq2, mdma);
-- 
1.8.4.2

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[PATCH 0/3] dmaengine: mpc512x: add device tree binding document and DMA channel lookup

[Alexander Popov]

This patch series introduces a device tree binding document for
the MPC512x DMA controller and adds device tree based DMA channel lookup
for it.

Alexander Popov (3):
  dmaengine: mpc512x: add device tree binding document
  dmaengine: of: add common xlate function for matching by channel id
  dmaengine: mpc512x: register for device tree channel lookup

 .../devicetree/bindings/dma/mpc512x-dma.txt| 40 ++
 arch/powerpc/boot/dts/mpc5121.dtsi |  1 +
 drivers/dma/mpc512x_dma.c  | 13 ++-
 drivers/dma/of-dma.c   | 35 +++
 include/linux/of_dma.h |  4 +++
 5 files changed, 92 insertions(+), 1 deletion(-)
 create mode 100644 Documentation/devicetree/bindings/dma/mpc512x-dma.txt

-- 
1.8.4.2

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[PATCH 2/3] dmaengine: of: add common xlate function for matching by channel id

[Alexander Popov]

This patch adds a new common OF dma xlate callback function which will match a
channel by it's id. The binding expects one integer argument which it will use 
to
lookup the channel by the id.

Unlike of_dma_simple_xlate this function is able to handle a system with
multiple DMA controllers. When registering the of dma provider with
of_dma_controller_register a pointer to the dma_device struct which is
associated with the dt node needs to passed as the data parameter.
New function will use this pointer to match only channels which belong to the
specified DMA controller.

Signed-off-by: Alexander Popov 
---
 drivers/dma/of-dma.c   | 35 +++
 include/linux/of_dma.h |  4 
 2 files changed, 39 insertions(+)

diff --git a/drivers/dma/of-dma.c b/drivers/dma/of-dma.c
index e8fe9dc..d5fbeaa 100644
--- a/drivers/dma/of-dma.c
+++ b/drivers/dma/of-dma.c
@@ -218,3 +218,38 @@ struct dma_chan *of_dma_simple_xlate(struct 
of_phandle_args *dma_spec,
&dma_spec->args[0]);
 }
 EXPORT_SYMBOL_GPL(of_dma_simple_xlate);
+
+/**
+ * of_dma_xlate_by_chan_id - Translate dt property to DMA channel by channel id
+ * @dma_spec:  pointer to DMA specifier as found in the device tree
+ * @of_dma:pointer to DMA controller data
+ *
+ * This function can be used as the of xlate callback for DMA driver which 
wants
+ * to match the channel based on the channel id. When using this xlate function
+ * the #dma-cells propety of the DMA controller dt node needs to be set to 1.
+ * The data parameter of of_dma_controller_register must be a pointer to the
+ * dma_device struct the function should match upon.
+ *
+ * Returns pointer to appropriate dma channel on success or NULL on error.
+ */
+struct dma_chan *of_dma_xlate_by_chan_id(struct of_phandle_args *dma_spec,
+struct of_dma *ofdma)
+{
+   struct dma_device *dev = ofdma->of_dma_data;
+   struct dma_chan *chan, *candidate = NULL;
+
+   if (!dev || dma_spec->args_count != 1)
+   return NULL;
+
+   list_for_each_entry(chan, &dev->channels, device_node)
+   if (chan->chan_id == dma_spec->args[0]) {
+   candidate = chan;
+   break;
+   }
+
+   if (!candidate)
+   return NULL;
+
+   return dma_get_slave_channel(candidate);
+}
+EXPORT_SYMBOL_GPL(of_dma_xlate_by_chan_id);
diff --git a/include/linux/of_dma.h b/include/linux/of_dma.h
index ae36298..56bc026 100644
--- a/include/linux/of_dma.h
+++ b/include/linux/of_dma.h
@@ -41,6 +41,8 @@ extern struct dma_chan *of_dma_request_slave_channel(struct 
device_node *np,
 const char *name);
 extern struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_spec,
struct of_dma *ofdma);
+extern struct dma_chan *of_dma_xlate_by_chan_id(struct of_phandle_args 
*dma_spec,
+   struct of_dma *ofdma);
 #else
 static inline int of_dma_controller_register(struct device_node *np,
struct dma_chan *(*of_dma_xlate)
@@ -66,6 +68,8 @@ static inline struct dma_chan *of_dma_simple_xlate(struct 
of_phandle_args *dma_s
return NULL;
 }
 
+#define of_dma_xlate_by_chan_id NULL
+
 #endif
 
 #endif /* __LINUX_OF_DMA_H */
-- 
1.8.4.2

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Re: [PATCH RFC v13 0/5] MPC512x DMA slave s/g support, OF DMA lookup

[Alexander Popov]

Thank you, Vinod

2014-05-22 9:10 GMT+04:00 Vinod Koul :
> On Thu, May 15, 2014 at 06:15:30PM +0400, Alexander Popov wrote:
>> Changes in v13:
>>  A new patch (part 1/5) is added to this series.
>>  Part 2/5:
>>  - fix style issue;
>>  - improve comments;
>
> You need to cc DT- list for 3 to 5 patches. Need ack before we can apply.
In this v13 series parts 0/5, 3/5, 4/5 and 5/5 do have "Cc:
devicetree@vger.kernel.org".

> I suspect 4/5 should come first out of these 3.
Ok. I'll send v14 soon.

> Also in future pls use right subsystem name "dmaengine". Also why are these
> tagged as RFC still?
Ok, thanks.

Best regards,
Alexander
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[PATCH RFC v13 0/5] MPC512x DMA slave s/g support, OF DMA lookup

[Alexander Popov]

2013/7/14 Gerhard Sittig :
> this series
> - introduces slave s/g support (that's support for DMA transfers which
>involve peripherals in contrast to mem-to-mem transfers)
> - adds device tree based lookup support for DMA channels
> - combines floating patches and related feedback which already covered
>several aspects of what the suggested LPB driver needs, to demonstrate
>how integration might be done

...

Changes in v12:
 A new patch (part 2/7) is added to this series.
 Part 6/7:
 - change the description of 'compatible' property according part 2/7;
 - improve the document according Gerhard's feedback;

Parts 1/7, 2/7 and 4/7 have been applied by Vinod Koul and
are excluded from v13.

Changes in v13:
 A new patch (part 1/5) is added to this series.
 Part 2/5:
 - fix style issue;
 - improve comments;

> known issues:
> - it's yet to get confirmed whether MPC8308 can use slave support or
>whether the DMA controller's driver shall actively reject it, the
>information that's available so far suggests that peripheral transfers
>to IP bus attached I/O is useful and shall not get blocked right away


Alexander Popov (5):
  dmaengine: fix comment typo
  dma: mpc512x: add support for peripheral transfers
  dma: of: add common xlate function for matching by channel id
  dma: mpc512x: add device tree binding document
  dma: mpc512x: register for device tree channel lookup

 .../devicetree/bindings/dma/mpc512x-dma.txt|  40 
 arch/powerpc/boot/dts/mpc5121.dtsi |   1 +
 drivers/dma/mpc512x_dma.c  | 257 -
 drivers/dma/of-dma.c   |  35 +++
 include/linux/dmaengine.h  |   2 +-
 include/linux/of_dma.h |   4 +
 6 files changed, 332 insertions(+), 7 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/dma/mpc512x-dma.txt

-- 
1.8.4.2

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[PATCH RFC v13 3/5] dma: of: add common xlate function for matching by channel id

[Alexander Popov]

This patch adds a new common OF dma xlate callback function which will match a
channel by it's id. The binding expects one integer argument which it will use 
to
lookup the channel by the id.

Unlike of_dma_simple_xlate this function is able to handle a system with
multiple DMA controllers. When registering the of dma provider with
of_dma_controller_register a pointer to the dma_device struct which is
associated with the dt node needs to passed as the data parameter.
New function will use this pointer to match only channels which belong to the
specified DMA controller.

Signed-off-by: Alexander Popov 
---
 drivers/dma/of-dma.c   | 35 +++
 include/linux/of_dma.h |  4 
 2 files changed, 39 insertions(+)

diff --git a/drivers/dma/of-dma.c b/drivers/dma/of-dma.c
index e8fe9dc..d5fbeaa 100644
--- a/drivers/dma/of-dma.c
+++ b/drivers/dma/of-dma.c
@@ -218,3 +218,38 @@ struct dma_chan *of_dma_simple_xlate(struct 
of_phandle_args *dma_spec,
&dma_spec->args[0]);
 }
 EXPORT_SYMBOL_GPL(of_dma_simple_xlate);
+
+/**
+ * of_dma_xlate_by_chan_id - Translate dt property to DMA channel by channel id
+ * @dma_spec:  pointer to DMA specifier as found in the device tree
+ * @of_dma:pointer to DMA controller data
+ *
+ * This function can be used as the of xlate callback for DMA driver which 
wants
+ * to match the channel based on the channel id. When using this xlate function
+ * the #dma-cells propety of the DMA controller dt node needs to be set to 1.
+ * The data parameter of of_dma_controller_register must be a pointer to the
+ * dma_device struct the function should match upon.
+ *
+ * Returns pointer to appropriate dma channel on success or NULL on error.
+ */
+struct dma_chan *of_dma_xlate_by_chan_id(struct of_phandle_args *dma_spec,
+struct of_dma *ofdma)
+{
+   struct dma_device *dev = ofdma->of_dma_data;
+   struct dma_chan *chan, *candidate = NULL;
+
+   if (!dev || dma_spec->args_count != 1)
+   return NULL;
+
+   list_for_each_entry(chan, &dev->channels, device_node)
+   if (chan->chan_id == dma_spec->args[0]) {
+   candidate = chan;
+   break;
+   }
+
+   if (!candidate)
+   return NULL;
+
+   return dma_get_slave_channel(candidate);
+}
+EXPORT_SYMBOL_GPL(of_dma_xlate_by_chan_id);
diff --git a/include/linux/of_dma.h b/include/linux/of_dma.h
index ae36298..56bc026 100644
--- a/include/linux/of_dma.h
+++ b/include/linux/of_dma.h
@@ -41,6 +41,8 @@ extern struct dma_chan *of_dma_request_slave_channel(struct 
device_node *np,
 const char *name);
 extern struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_spec,
struct of_dma *ofdma);
+extern struct dma_chan *of_dma_xlate_by_chan_id(struct of_phandle_args 
*dma_spec,
+   struct of_dma *ofdma);
 #else
 static inline int of_dma_controller_register(struct device_node *np,
struct dma_chan *(*of_dma_xlate)
@@ -66,6 +68,8 @@ static inline struct dma_chan *of_dma_simple_xlate(struct 
of_phandle_args *dma_s
return NULL;
 }
 
+#define of_dma_xlate_by_chan_id NULL
+
 #endif
 
 #endif /* __LINUX_OF_DMA_H */
-- 
1.8.4.2

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[PATCH RFC v13 4/5] dma: mpc512x: add device tree binding document

[Alexander Popov]

Introduce a device tree binding document for the MPC512x DMA controller

Signed-off-by: Alexander Popov 
---
 .../devicetree/bindings/dma/mpc512x-dma.txt| 40 ++
 1 file changed, 40 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/dma/mpc512x-dma.txt

diff --git a/Documentation/devicetree/bindings/dma/mpc512x-dma.txt 
b/Documentation/devicetree/bindings/dma/mpc512x-dma.txt
new file mode 100644
index 000..b1cbc3f
--- /dev/null
+++ b/Documentation/devicetree/bindings/dma/mpc512x-dma.txt
@@ -0,0 +1,40 @@
+* Freescale MPC512x and MPC8308 DMA Controller
+
+The DMA controller in Freescale MPC512x and MPC8308 SoCs can move
+blocks of memory contents between memory and peripherals or
+from memory to memory.
+
+Refer to "Generic DMA Controller and DMA request bindings" in
+the dma/dma.txt file for a more detailed description of binding.
+
+Required properties:
+- compatible: Should be "fsl,mpc5121-dma" or "fsl,mpc8308-dma"
+- reg: Address and size of the DMA controller's register set
+- Interrupt for the DMA controller. Syntax of interrupt client node
+   is described in interrupt-controller/interrupts.txt
+
+Optional properties:
+- #dma-cells: The length of the DMA specifier, must be <1>.
+   Each channel of this DMA controller has a peripheral request line,
+   this assignment is fixed in hardware. The cell in dmas property
+   of a client device represents the channel number
+
+Example:
+
+   dma0: dma@14000 {
+   compatible = "fsl,mpc5121-dma";
+   reg = <0x14000 0x1800>;
+   interrupts = <65 0x8>;
+   #dma-cells = <1>;
+   };
+
+DMA clients must use the format described in dma/dma.txt
+
+Example:
+
+   sdhc@1500 {
+   compatible = "fsl,mpc5121-sdhc";
+   /* ... */
+   dmas = <&dma0 30>;
+   dma-names = "rx-tx";
+   };
-- 
1.8.4.2

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[PATCH RFC v13 5/5] dma: mpc512x: register for device tree channel lookup

[Alexander Popov]

Register the controller for device tree based lookup of DMA channels
(non-fatal for backwards compatibility with older device trees) and
provide the '#dma-cells' property in the shared mpc5121.dtsi file

Signed-off-by: Alexander Popov 
---
 arch/powerpc/boot/dts/mpc5121.dtsi |  1 +
 drivers/dma/mpc512x_dma.c  | 13 -
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/boot/dts/mpc5121.dtsi 
b/arch/powerpc/boot/dts/mpc5121.dtsi
index 2c0e155..7f9d14f 100644
--- a/arch/powerpc/boot/dts/mpc5121.dtsi
+++ b/arch/powerpc/boot/dts/mpc5121.dtsi
@@ -498,6 +498,7 @@
compatible = "fsl,mpc5121-dma";
reg = <0x14000 0x1800>;
interrupts = <65 0x8>;
+   #dma-cells = <1>;
};
};
 
diff --git a/drivers/dma/mpc512x_dma.c b/drivers/dma/mpc512x_dma.c
index 2ad4373..881db2b 100644
--- a/drivers/dma/mpc512x_dma.c
+++ b/drivers/dma/mpc512x_dma.c
@@ -53,6 +53,7 @@
 #include 
 #include 
 #include 
+#include 
 #include 
 
 #include 
@@ -1036,7 +1037,15 @@ static int mpc_dma_probe(struct platform_device *op)
if (retval)
goto err_free2;
 
-   return retval;
+   /* Register with OF helpers for DMA lookups (nonfatal) */
+   if (dev->of_node) {
+   retval = of_dma_controller_register(dev->of_node,
+   of_dma_xlate_by_chan_id, mdma);
+   if (retval)
+   dev_warn(dev, "Could not register for OF lookup\n");
+   }
+
+   return 0;
 
 err_free2:
if (mdma->is_mpc8308)
@@ -1057,6 +1066,8 @@ static int mpc_dma_remove(struct platform_device *op)
struct device *dev = &op->dev;
struct mpc_dma *mdma = dev_get_drvdata(dev);
 
+   if (dev->of_node)
+   of_dma_controller_free(dev->of_node);
dma_async_device_unregister(&mdma->dma);
if (mdma->is_mpc8308) {
free_irq(mdma->irq2, mdma);
-- 
1.8.4.2

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Re: [PATCH RFC v12 0/7] MPC512x DMA slave s/g support, OF DMA lookup

[Alexander Popov]

Hello

2014-04-23 17:53 GMT+04:00 Alexander Popov :
> Changes in v12:
>  A new patch (part 2/7) is added to this series.
>  Part 6/7:
>  - change the description of 'compatible' property according part 2/7;
>  - improve the document according Gerhard's feedback;

Could I have a feedback? Is the binding document fine now?
Thanks!

> Alexander Popov (7):
>   dma: mpc512x: reorder mpc8308 specific instructions
>   dma: mpc512x: separate 'compatible' values for MPC512x and MPC8308
>   dma: mpc512x: add support for peripheral transfers
>   dma: mpc512x: fix freeing resources in mpc_dma_probe() and
> mpc_dma_remove()
>   dma: of: add common xlate function for matching by channel id
>   dma: mpc512x: add device tree binding document
>   dma: mpc512x: register for device tree channel lookup
>
>  .../devicetree/bindings/dma/mpc512x-dma.txt|  40 +++
>  arch/powerpc/boot/dts/mpc5121.dtsi |   1 +
>  arch/powerpc/boot/dts/mpc8308_p1m.dts  |   2 +-
>  arch/powerpc/boot/dts/mpc8308rdb.dts   |   2 +-
>  drivers/dma/mpc512x_dma.c  | 346 
> ++---
>  drivers/dma/of-dma.c   |  35 +++
>  include/linux/of_dma.h |   4 +
>  7 files changed, 390 insertions(+), 40 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/dma/mpc512x-dma.txt
>
> --
> 1.8.4.2
>

Best regards,
Alexander
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[PATCH RFC v12 2/7] dma: mpc512x: separate 'compatible' values for MPC512x and MPC8308

[Alexander Popov]

MPC512x and MPC8308 have similar DMA controllers, but are independent SoCs.
DMA controller driver should have separate 'compatible' values for these SoCs.

Signed-off-by: Alexander Popov 
---
 arch/powerpc/boot/dts/mpc8308_p1m.dts | 2 +-
 arch/powerpc/boot/dts/mpc8308rdb.dts  | 2 +-
 drivers/dma/mpc512x_dma.c | 1 +
 3 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/boot/dts/mpc8308_p1m.dts 
b/arch/powerpc/boot/dts/mpc8308_p1m.dts
index 651e4f5..57f86cd 100644
--- a/arch/powerpc/boot/dts/mpc8308_p1m.dts
+++ b/arch/powerpc/boot/dts/mpc8308_p1m.dts
@@ -296,7 +296,7 @@
};
 
dma@2c000 {
-   compatible = "fsl,mpc8308-dma", "fsl,mpc5121-dma";
+   compatible = "fsl,mpc8308-dma";
reg = <0x2c000 0x1800>;
interrupts = <3 0x8
94 0x8>;
diff --git a/arch/powerpc/boot/dts/mpc8308rdb.dts 
b/arch/powerpc/boot/dts/mpc8308rdb.dts
index 9ce45f2..d0211f0 100644
--- a/arch/powerpc/boot/dts/mpc8308rdb.dts
+++ b/arch/powerpc/boot/dts/mpc8308rdb.dts
@@ -265,7 +265,7 @@
};
 
dma@2c000 {
-   compatible = "fsl,mpc8308-dma", "fsl,mpc5121-dma";
+   compatible = "fsl,mpc8308-dma";
reg = <0x2c000 0x1800>;
interrupts = <3 0x8
94 0x8>;
diff --git a/drivers/dma/mpc512x_dma.c b/drivers/dma/mpc512x_dma.c
index 2ce248b..0b17f4d 100644
--- a/drivers/dma/mpc512x_dma.c
+++ b/drivers/dma/mpc512x_dma.c
@@ -815,6 +815,7 @@ static int mpc_dma_remove(struct platform_device *op)
 
 static struct of_device_id mpc_dma_match[] = {
{ .compatible = "fsl,mpc5121-dma", },
+   { .compatible = "fsl,mpc8308-dma", },
{},
 };
 
-- 
1.8.4.2

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[PATCH RFC v12 5/7] dma: of: add common xlate function for matching by channel id

[Alexander Popov]

This patch adds a new common OF dma xlate callback function which will match a
channel by it's id. The binding expects one integer argument which it will use 
to
lookup the channel by the id.

Unlike of_dma_simple_xlate this function is able to handle a system with
multiple DMA controllers. When registering the of dma provider with
of_dma_controller_register a pointer to the dma_device struct which is
associated with the dt node needs to passed as the data parameter.
New function will use this pointer to match only channels which belong to the
specified DMA controller.

Signed-off-by: Alexander Popov 
---
 drivers/dma/of-dma.c   | 35 +++
 include/linux/of_dma.h |  4 
 2 files changed, 39 insertions(+)

diff --git a/drivers/dma/of-dma.c b/drivers/dma/of-dma.c
index e8fe9dc..d5fbeaa 100644
--- a/drivers/dma/of-dma.c
+++ b/drivers/dma/of-dma.c
@@ -218,3 +218,38 @@ struct dma_chan *of_dma_simple_xlate(struct 
of_phandle_args *dma_spec,
&dma_spec->args[0]);
 }
 EXPORT_SYMBOL_GPL(of_dma_simple_xlate);
+
+/**
+ * of_dma_xlate_by_chan_id - Translate dt property to DMA channel by channel id
+ * @dma_spec:  pointer to DMA specifier as found in the device tree
+ * @of_dma:pointer to DMA controller data
+ *
+ * This function can be used as the of xlate callback for DMA driver which 
wants
+ * to match the channel based on the channel id. When using this xlate function
+ * the #dma-cells propety of the DMA controller dt node needs to be set to 1.
+ * The data parameter of of_dma_controller_register must be a pointer to the
+ * dma_device struct the function should match upon.
+ *
+ * Returns pointer to appropriate dma channel on success or NULL on error.
+ */
+struct dma_chan *of_dma_xlate_by_chan_id(struct of_phandle_args *dma_spec,
+struct of_dma *ofdma)
+{
+   struct dma_device *dev = ofdma->of_dma_data;
+   struct dma_chan *chan, *candidate = NULL;
+
+   if (!dev || dma_spec->args_count != 1)
+   return NULL;
+
+   list_for_each_entry(chan, &dev->channels, device_node)
+   if (chan->chan_id == dma_spec->args[0]) {
+   candidate = chan;
+   break;
+   }
+
+   if (!candidate)
+   return NULL;
+
+   return dma_get_slave_channel(candidate);
+}
+EXPORT_SYMBOL_GPL(of_dma_xlate_by_chan_id);
diff --git a/include/linux/of_dma.h b/include/linux/of_dma.h
index ae36298..56bc026 100644
--- a/include/linux/of_dma.h
+++ b/include/linux/of_dma.h
@@ -41,6 +41,8 @@ extern struct dma_chan *of_dma_request_slave_channel(struct 
device_node *np,
 const char *name);
 extern struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_spec,
struct of_dma *ofdma);
+extern struct dma_chan *of_dma_xlate_by_chan_id(struct of_phandle_args 
*dma_spec,
+   struct of_dma *ofdma);
 #else
 static inline int of_dma_controller_register(struct device_node *np,
struct dma_chan *(*of_dma_xlate)
@@ -66,6 +68,8 @@ static inline struct dma_chan *of_dma_simple_xlate(struct 
of_phandle_args *dma_s
return NULL;
 }
 
+#define of_dma_xlate_by_chan_id NULL
+
 #endif
 
 #endif /* __LINUX_OF_DMA_H */
-- 
1.8.4.2

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[PATCH RFC v12 0/7] MPC512x DMA slave s/g support, OF DMA lookup

[Alexander Popov]

's yet to get confirmed whether MPC8308 can use slave support or
>whether the DMA controller's driver shall actively reject it, the
>information that's available so far suggests that peripheral transfers
>to IP bus attached I/O is useful and shall not get blocked right away
 - adding support for transfers which don't increment the RAM address or
do increment the peripheral "port's" address is easy with
this implementation; but which options of the common API
should be used for specifying such transfers?


Alexander Popov (7):
  dma: mpc512x: reorder mpc8308 specific instructions
  dma: mpc512x: separate 'compatible' values for MPC512x and MPC8308
  dma: mpc512x: add support for peripheral transfers
  dma: mpc512x: fix freeing resources in mpc_dma_probe() and
mpc_dma_remove()
  dma: of: add common xlate function for matching by channel id
  dma: mpc512x: add device tree binding document
  dma: mpc512x: register for device tree channel lookup

 .../devicetree/bindings/dma/mpc512x-dma.txt|  40 +++
 arch/powerpc/boot/dts/mpc5121.dtsi |   1 +
 arch/powerpc/boot/dts/mpc8308_p1m.dts  |   2 +-
 arch/powerpc/boot/dts/mpc8308rdb.dts   |   2 +-
 drivers/dma/mpc512x_dma.c  | 346 ++---
 drivers/dma/of-dma.c   |  35 +++
 include/linux/of_dma.h |   4 +
 7 files changed, 390 insertions(+), 40 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/dma/mpc512x-dma.txt

-- 
1.8.4.2

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[PATCH RFC v12 6/7] dma: mpc512x: add device tree binding document

[Alexander Popov]

Introduce a device tree binding document for the MPC512x DMA controller

Signed-off-by: Alexander Popov 
---
 .../devicetree/bindings/dma/mpc512x-dma.txt| 40 ++
 1 file changed, 40 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/dma/mpc512x-dma.txt

diff --git a/Documentation/devicetree/bindings/dma/mpc512x-dma.txt 
b/Documentation/devicetree/bindings/dma/mpc512x-dma.txt
new file mode 100644
index 000..b1cbc3f
--- /dev/null
+++ b/Documentation/devicetree/bindings/dma/mpc512x-dma.txt
@@ -0,0 +1,40 @@
+* Freescale MPC512x and MPC8308 DMA Controller
+
+The DMA controller in Freescale MPC512x and MPC8308 SoCs can move
+blocks of memory contents between memory and peripherals or
+from memory to memory.
+
+Refer to "Generic DMA Controller and DMA request bindings" in
+the dma/dma.txt file for a more detailed description of binding.
+
+Required properties:
+- compatible: Should be "fsl,mpc5121-dma" or "fsl,mpc8308-dma"
+- reg: Address and size of the DMA controller's register set
+- Interrupt for the DMA controller. Syntax of interrupt client node
+   is described in interrupt-controller/interrupts.txt
+
+Optional properties:
+- #dma-cells: The length of the DMA specifier, must be <1>.
+   Each channel of this DMA controller has a peripheral request line,
+   this assignment is fixed in hardware. The cell in dmas property
+   of a client device represents the channel number
+
+Example:
+
+   dma0: dma@14000 {
+   compatible = "fsl,mpc5121-dma";
+   reg = <0x14000 0x1800>;
+   interrupts = <65 0x8>;
+   #dma-cells = <1>;
+   };
+
+DMA clients must use the format described in dma/dma.txt
+
+Example:
+
+   sdhc@1500 {
+   compatible = "fsl,mpc5121-sdhc";
+   /* ... */
+   dmas = <&dma0 30>;
+   dma-names = "rx-tx";
+   };
-- 
1.8.4.2

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[PATCH RFC v12 7/7] dma: mpc512x: register for device tree channel lookup

[Alexander Popov]

Register the controller for device tree based lookup of DMA channels
(non-fatal for backwards compatibility with older device trees) and
provide the '#dma-cells' property in the shared mpc5121.dtsi file

Signed-off-by: Alexander Popov 
---
 arch/powerpc/boot/dts/mpc5121.dtsi |  1 +
 drivers/dma/mpc512x_dma.c  | 13 -
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/boot/dts/mpc5121.dtsi 
b/arch/powerpc/boot/dts/mpc5121.dtsi
index 2c0e155..7f9d14f 100644
--- a/arch/powerpc/boot/dts/mpc5121.dtsi
+++ b/arch/powerpc/boot/dts/mpc5121.dtsi
@@ -498,6 +498,7 @@
compatible = "fsl,mpc5121-dma";
reg = <0x14000 0x1800>;
interrupts = <65 0x8>;
+   #dma-cells = <1>;
};
};
 
diff --git a/drivers/dma/mpc512x_dma.c b/drivers/dma/mpc512x_dma.c
index d2c5f79..fa0614e 100644
--- a/drivers/dma/mpc512x_dma.c
+++ b/drivers/dma/mpc512x_dma.c
@@ -52,6 +52,7 @@
 #include 
 #include 
 #include 
+#include 
 #include 
 
 #include 
@@ -1031,7 +1032,15 @@ static int mpc_dma_probe(struct platform_device *op)
if (retval)
goto err_free2;
 
-   return retval;
+   /* Register with OF helpers for DMA lookups (nonfatal) */
+   if (dev->of_node) {
+   retval = of_dma_controller_register(dev->of_node,
+   of_dma_xlate_by_chan_id, mdma);
+   if (retval)
+   dev_warn(dev, "Could not register for OF lookup\n");
+   }
+
+   return 0;
 
 err_free2:
if (mdma->is_mpc8308)
@@ -1052,6 +1061,8 @@ static int mpc_dma_remove(struct platform_device *op)
struct device *dev = &op->dev;
struct mpc_dma *mdma = dev_get_drvdata(dev);
 
+   if (dev->of_node)
+   of_dma_controller_free(dev->of_node);
dma_async_device_unregister(&mdma->dma);
if (mdma->is_mpc8308) {
free_irq(mdma->irq2, mdma);
-- 
1.8.4.2

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Re: [PATCH RFC v11 5/6] dma: mpc512x: add device tree binding document

[Alexander Popov]

Thanks for your reply, Gerhard

2014-04-17 0:44 GMT+04:00 Gerhard Sittig :
> On Tue, 2014-04-15 at 14:54 +0400, Alexander Popov wrote:
>>
>> Introduce a device tree binding document for the MPC512x DMA controller
>>
>> Signed-off-by: Gerhard Sittig 
>> Signed-off-by: Alexander Popov 
>
> I'm not certain whether the attribution is right.  Is the S-o-b
> appropriate when the patch is not "from" me? As I've stated
> before, it's OK if you pick up and extend what I provide, but
> please don't pretend that I wrote what you did,
Thanks. I've read the corresponding part of
Documentation/SubmittingPatches once again and now I see
my mistake.

> and don't pretend
> that I ACKed or passed along your submission when I didn't.
I didn't have any malicious intent.

> This binding certainly needs further improvement to become a good
> one.  As I've communicated in the past, I was rather ignorant
> "back then" when I wrote v1 and v2 of the RFC.  We have learned
> something in the meantime.  Though I admit having gone silent
> after several review iterations.  Assumed you would pick up
> information that showed up several times on public lists.
>
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/dma/mpc512x-dma.txt
>> @@ -0,0 +1,51 @@
>> +* Freescale MPC512x and MPC8308 DMA Controller
>> +
>> +The DMA controller in the Freescale MPC512x and MPC8308 SoCs can move
>> +blocks of memory contents between memory and peripherals or
>> +from memory to memory.
>> +
>> +Refer to the "Generic DMA Controller and DMA request bindings" in
>> +the dma/dma.txt file for a more detailed description of binding.
>> +
>> +* DMA controller
>> +
>> +Required properties:
>> +- compatible: Should be one of
>> + "fsl,mpc5121-dma"
>> + "fsl,mpc8308-dma", "fsl,mpc5121-dma"
>
> is this a duplicate?  looks funny, needs a fix
>
> or is it a requirement that for MPC8308 you need to provide both
> compatible strings?  that would be wrong, as MPC8308 certainly is
> not an MPC5121
>
> a quick search reveals: the drivers/dma/mpc512x_dma.c Linux
> driver implementation is wrong, it should match on both strings;
> expecting the MPC8308 to disguise as an MPC5121 when it's not is
> inappropriate (and only went unnoticed because of missing
> bindings, I guess)
I can try to fix that and add a new patch to the series.

>> +- reg: Address and size of the DMA controller's register set
>> +- interrupts: Interrupt for the DMA controller. Generic interrupt client 
>> node
>> + is described in interrupt-controller/interrupts.txt
>
> 'interrupts' only works in combinations with 'interrupt-parent',
> that actual .dts files don't have the latter in the nodes is an
> implementation detail but not a binding's requirement
Excuse me, I didn't understand your point.

> and an alternative method of specifying interrupts was introduced
> recently, a reference to the common binding without naming one
> specific property name could be most appropriate
Excuse me, I haven't found such an example.

>> +
>> +Optional properties:
>> +- #dma-cells: The length of the DMA specifier, must be <1> since
>> + the DMA controller uses a fixed assignment of request lines
>> + per channel. Refer to dma/dma.txt for the detailed description
>> + of this property
>
> I'm afraid that a generic/common document does not and cannot
> describe the specific semantics of this provider's cells
Ok, I see.

> this binding should explicitly mention that the number of cells
> needs to be one, and that this one cell is the DMA channel (which
> translates to "peripheral request line"), because these
> assigments are fixed in hardware
Ok.

>> +
>> +Example:
>> +
>> + dma0: dma@14000 {
>> + compatible = "fsl,mpc5121-dma";
>> + reg = <0x14000 0x1800>;
>> + interrupts = <65 0x8>;
>> + #dma-cells = <1>;
>> + };
>> +
>> +* DMA client
>
> the DMA provider's binding probably need not discuss client
> specs, a reference to the common binding should suffice if it's
> appropriate at all
Ok.

Best regards,
Alexander
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[PATCH RFC v11 6/6] dma: mpc512x: register for device tree channel lookup

[Alexander Popov]

Register the controller for device tree based lookup of DMA channels
(non-fatal for backwards compatibility with older device trees) and
provide the '#dma-cells' property in the shared mpc5121.dtsi file

Signed-off-by: Gerhard Sittig 
Signed-off-by: Alexander Popov 
---
 arch/powerpc/boot/dts/mpc5121.dtsi |  1 +
 drivers/dma/mpc512x_dma.c  | 13 -
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/boot/dts/mpc5121.dtsi 
b/arch/powerpc/boot/dts/mpc5121.dtsi
index 2c0e155..7f9d14f 100644
--- a/arch/powerpc/boot/dts/mpc5121.dtsi
+++ b/arch/powerpc/boot/dts/mpc5121.dtsi
@@ -498,6 +498,7 @@
compatible = "fsl,mpc5121-dma";
reg = <0x14000 0x1800>;
interrupts = <65 0x8>;
+   #dma-cells = <1>;
};
};
 
diff --git a/drivers/dma/mpc512x_dma.c b/drivers/dma/mpc512x_dma.c
index 1b90b3b..ab70012 100644
--- a/drivers/dma/mpc512x_dma.c
+++ b/drivers/dma/mpc512x_dma.c
@@ -52,6 +52,7 @@
 #include 
 #include 
 #include 
+#include 
 #include 
 
 #include 
@@ -1031,7 +1032,15 @@ static int mpc_dma_probe(struct platform_device *op)
if (retval)
goto err_free2;
 
-   return retval;
+   /* Register with OF helpers for DMA lookups (nonfatal) */
+   if (dev->of_node) {
+   retval = of_dma_controller_register(dev->of_node,
+   of_dma_xlate_by_chan_id, mdma);
+   if (retval)
+   dev_warn(dev, "Could not register for OF lookup\n");
+   }
+
+   return 0;
 
 err_free2:
if (mdma->is_mpc8308)
@@ -1052,6 +1061,8 @@ static int mpc_dma_remove(struct platform_device *op)
struct device *dev = &op->dev;
struct mpc_dma *mdma = dev_get_drvdata(dev);
 
+   if (dev->of_node)
+   of_dma_controller_free(dev->of_node);
dma_async_device_unregister(&mdma->dma);
if (mdma->is_mpc8308) {
free_irq(mdma->irq2, mdma);
-- 
1.8.4.2

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[PATCH RFC v11 5/6] dma: mpc512x: add device tree binding document

[Alexander Popov]

Introduce a device tree binding document for the MPC512x DMA controller

Signed-off-by: Gerhard Sittig 
Signed-off-by: Alexander Popov 
---
 .../devicetree/bindings/dma/mpc512x-dma.txt| 51 ++
 1 file changed, 51 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/dma/mpc512x-dma.txt

diff --git a/Documentation/devicetree/bindings/dma/mpc512x-dma.txt 
b/Documentation/devicetree/bindings/dma/mpc512x-dma.txt
new file mode 100644
index 000..92eb0d9
--- /dev/null
+++ b/Documentation/devicetree/bindings/dma/mpc512x-dma.txt
@@ -0,0 +1,51 @@
+* Freescale MPC512x and MPC8308 DMA Controller
+
+The DMA controller in the Freescale MPC512x and MPC8308 SoCs can move
+blocks of memory contents between memory and peripherals or
+from memory to memory.
+
+Refer to the "Generic DMA Controller and DMA request bindings" in
+the dma/dma.txt file for a more detailed description of binding.
+
+* DMA controller
+
+Required properties:
+- compatible: Should be one of
+   "fsl,mpc5121-dma"
+   "fsl,mpc8308-dma", "fsl,mpc5121-dma"
+- reg: Address and size of the DMA controller's register set
+- interrupts: Interrupt for the DMA controller. Generic interrupt client node
+   is described in interrupt-controller/interrupts.txt
+
+Optional properties:
+- #dma-cells: The length of the DMA specifier, must be <1> since
+   the DMA controller uses a fixed assignment of request lines
+   per channel. Refer to dma/dma.txt for the detailed description
+   of this property
+
+Example:
+
+   dma0: dma@14000 {
+   compatible = "fsl,mpc5121-dma";
+   reg = <0x14000 0x1800>;
+   interrupts = <65 0x8>;
+   #dma-cells = <1>;
+   };
+
+* DMA client
+
+Required properties:
+- dmas: List of one or more DMA request specifiers. One DMA request specifier
+   consists of a phandle to the DMA controller node followed by
+   the integer specifying the request line
+- dma-names: Contains an identifier string for each DMA request specifier.
+   Refer to dma/dma.txt for the description of this property
+
+Example:
+
+   sdhc@1500 {
+   compatible = "fsl,mpc5121-sdhc";
+   /* ... */
+   dmas = <&dma0 30>;
+   dma-names = "rx-tx";
+   };
-- 
1.8.4.2

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[PATCH RFC v11 0/6] MPC512x DMA slave s/g support, OF DMA lookup

[Alexander Popov]

ripheral transfers
>to IP bus attached I/O is useful and shall not get blocked right away
 - adding support for transfers which don't increment the RAM address or
do increment the peripheral "port's" address is easy with
this implementation; but which options of the common API
should be used for specifying such transfers?


Alexander Popov (6):
  dma: mpc512x: reorder mpc8308 specific instructions
  dma: mpc512x: add support for peripheral transfers
  dma: mpc512x: fix freeing resources in mpc_dma_probe() and
mpc_dma_remove()
  dma: of: Add common xlate function for matching by channel id
  dma: mpc512x: add device tree binding document
  dma: mpc512x: register for device tree channel lookup

 .../devicetree/bindings/dma/mpc512x-dma.txt|  51 +++
 arch/powerpc/boot/dts/mpc5121.dtsi |   1 +
 drivers/dma/mpc512x_dma.c  | 345 ++---
 drivers/dma/of-dma.c   |  35 +++
 include/linux/of_dma.h |   4 +
 5 files changed, 398 insertions(+), 38 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/dma/mpc512x-dma.txt

-- 
1.8.4.2

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[PATCH RFC v11 4/6] dma: of: Add common xlate function for matching by channel id

[Alexander Popov]

This patch adds a new common OF dma xlate callback function which will match a
channel by it's id. The binding expects one integer argument which it will use 
to
lookup the channel by the id.

Unlike of_dma_simple_xlate this function is able to handle a system with
multiple DMA controllers. When registering the of dma provider with
of_dma_controller_register a pointer to the dma_device struct which is
associated with the dt node needs to passed as the data parameter.
New function will use this pointer to match only channels which belong to the
specified DMA controller.

Signed-off-by: Alexander Popov 
---
 drivers/dma/of-dma.c   | 35 +++
 include/linux/of_dma.h |  4 
 2 files changed, 39 insertions(+)

diff --git a/drivers/dma/of-dma.c b/drivers/dma/of-dma.c
index e8fe9dc..d5fbeaa 100644
--- a/drivers/dma/of-dma.c
+++ b/drivers/dma/of-dma.c
@@ -218,3 +218,38 @@ struct dma_chan *of_dma_simple_xlate(struct 
of_phandle_args *dma_spec,
&dma_spec->args[0]);
 }
 EXPORT_SYMBOL_GPL(of_dma_simple_xlate);
+
+/**
+ * of_dma_xlate_by_chan_id - Translate dt property to DMA channel by channel id
+ * @dma_spec:  pointer to DMA specifier as found in the device tree
+ * @of_dma:pointer to DMA controller data
+ *
+ * This function can be used as the of xlate callback for DMA driver which 
wants
+ * to match the channel based on the channel id. When using this xlate function
+ * the #dma-cells propety of the DMA controller dt node needs to be set to 1.
+ * The data parameter of of_dma_controller_register must be a pointer to the
+ * dma_device struct the function should match upon.
+ *
+ * Returns pointer to appropriate dma channel on success or NULL on error.
+ */
+struct dma_chan *of_dma_xlate_by_chan_id(struct of_phandle_args *dma_spec,
+struct of_dma *ofdma)
+{
+   struct dma_device *dev = ofdma->of_dma_data;
+   struct dma_chan *chan, *candidate = NULL;
+
+   if (!dev || dma_spec->args_count != 1)
+   return NULL;
+
+   list_for_each_entry(chan, &dev->channels, device_node)
+   if (chan->chan_id == dma_spec->args[0]) {
+   candidate = chan;
+   break;
+   }
+
+   if (!candidate)
+   return NULL;
+
+   return dma_get_slave_channel(candidate);
+}
+EXPORT_SYMBOL_GPL(of_dma_xlate_by_chan_id);
diff --git a/include/linux/of_dma.h b/include/linux/of_dma.h
index ae36298..56bc026 100644
--- a/include/linux/of_dma.h
+++ b/include/linux/of_dma.h
@@ -41,6 +41,8 @@ extern struct dma_chan *of_dma_request_slave_channel(struct 
device_node *np,
 const char *name);
 extern struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_spec,
struct of_dma *ofdma);
+extern struct dma_chan *of_dma_xlate_by_chan_id(struct of_phandle_args 
*dma_spec,
+   struct of_dma *ofdma);
 #else
 static inline int of_dma_controller_register(struct device_node *np,
struct dma_chan *(*of_dma_xlate)
@@ -66,6 +68,8 @@ static inline struct dma_chan *of_dma_simple_xlate(struct 
of_phandle_args *dma_s
return NULL;
 }
 
+#define of_dma_xlate_by_chan_id NULL
+
 #endif
 
 #endif /* __LINUX_OF_DMA_H */
-- 
1.8.4.2

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Re: [PATCH RFC v10 0/6] MPC512x DMA slave s/g support, OF DMA lookup

[Alexander Popov]

Hello,

2014-03-20 18:47 GMT+04:00 Alexander Popov :
> Changes in v10:
>  Part 2/6:
>  - don't use direction field of dma_slave_config in mpc_dma_device_control()
> but store settings in mpc_dma_chan for both DMA_DEV_TO_MEM and
> DMA_MEM_TO_DEV cases; then retrieve the needed values in
> mpc_dma_prep_slave_sg();
>  - fix style issue and put 2014 instead of 2013;
>  Part 3/6:
>  - fix mpc_dma_probe() error path and mpc_dma_remove(): manually free IRQs and
> dispose IRQ mappings before devm_* takes care of other resources;
>  Part 6/6:
>  - change according the new part 3/6;
>  - fix style issue;

Excuse me, could I have a feedback?
Thanks!

> Alexander Popov (5):
>   dma: mpc512x: reorder mpc8308 specific instructions
>   dma: mpc512x: add support for peripheral transfers
>   dma: mpc512x: fix freeing resources in mpc_dma_probe() and
> mpc_dma_remove()
>   dma: of: Add common xlate function for matching by channel id
>   dma: mpc512x: register for device tree channel lookup
>
> Gerhard Sittig (1):
>   dma: mpc512x: add device tree binding document
>
>  .../devicetree/bindings/dma/mpc512x-dma.txt|  55 
>  arch/powerpc/boot/dts/mpc5121.dtsi |   1 +
>  drivers/dma/mpc512x_dma.c  | 345 
> ++---
>  drivers/dma/of-dma.c   |  35 +++
>  include/linux/of_dma.h |   4 +
>  5 files changed, 402 insertions(+), 38 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/dma/mpc512x-dma.txt
>
> --
> 1.8.4.2

Best regards,
Alexander
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[PATCH RFC v10 6/6] dma: mpc512x: register for device tree channel lookup

[Alexander Popov]

Register the controller for device tree based lookup of DMA channels
(non-fatal for backwards compatibility with older device trees) and
provide the '#dma-cells' property in the shared mpc5121.dtsi file

Signed-off-by: Gerhard Sittig 
Signed-off-by: Alexander Popov 
---
 arch/powerpc/boot/dts/mpc5121.dtsi |  1 +
 drivers/dma/mpc512x_dma.c  | 13 -
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/boot/dts/mpc5121.dtsi 
b/arch/powerpc/boot/dts/mpc5121.dtsi
index 2c0e155..7f9d14f 100644
--- a/arch/powerpc/boot/dts/mpc5121.dtsi
+++ b/arch/powerpc/boot/dts/mpc5121.dtsi
@@ -498,6 +498,7 @@
compatible = "fsl,mpc5121-dma";
reg = <0x14000 0x1800>;
interrupts = <65 0x8>;
+   #dma-cells = <1>;
};
};
 
diff --git a/drivers/dma/mpc512x_dma.c b/drivers/dma/mpc512x_dma.c
index 1b90b3b..ab70012 100644
--- a/drivers/dma/mpc512x_dma.c
+++ b/drivers/dma/mpc512x_dma.c
@@ -52,6 +52,7 @@
 #include 
 #include 
 #include 
+#include 
 #include 
 
 #include 
@@ -1031,7 +1032,15 @@ static int mpc_dma_probe(struct platform_device *op)
if (retval)
goto err_free2;
 
-   return retval;
+   /* Register with OF helpers for DMA lookups (nonfatal) */
+   if (dev->of_node) {
+   retval = of_dma_controller_register(dev->of_node,
+   of_dma_xlate_by_chan_id, mdma);
+   if (retval)
+   dev_warn(dev, "Could not register for OF lookup\n");
+   }
+
+   return 0;
 
 err_free2:
if (mdma->is_mpc8308)
@@ -1052,6 +1061,8 @@ static int mpc_dma_remove(struct platform_device *op)
struct device *dev = &op->dev;
struct mpc_dma *mdma = dev_get_drvdata(dev);
 
+   if (dev->of_node)
+   of_dma_controller_free(dev->of_node);
dma_async_device_unregister(&mdma->dma);
if (mdma->is_mpc8308) {
free_irq(mdma->irq2, mdma);
-- 
1.8.4.2

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[PATCH RFC v10 4/6] dma: of: Add common xlate function for matching by channel id

[Alexander Popov]

This patch adds a new common OF dma xlate callback function which will match a
channel by it's id. The binding expects one integer argument which it will use 
to
lookup the channel by the id.

Unlike of_dma_simple_xlate this function is able to handle a system with
multiple DMA controllers. When registering the of dma provider with
of_dma_controller_register a pointer to the dma_device struct which is
associated with the dt node needs to passed as the data parameter.
New function will use this pointer to match only channels which belong to the
specified DMA controller.

Signed-off-by: Alexander Popov 
---
 drivers/dma/of-dma.c   | 35 +++
 include/linux/of_dma.h |  4 
 2 files changed, 39 insertions(+)

diff --git a/drivers/dma/of-dma.c b/drivers/dma/of-dma.c
index e8fe9dc..d5fbeaa 100644
--- a/drivers/dma/of-dma.c
+++ b/drivers/dma/of-dma.c
@@ -218,3 +218,38 @@ struct dma_chan *of_dma_simple_xlate(struct 
of_phandle_args *dma_spec,
&dma_spec->args[0]);
 }
 EXPORT_SYMBOL_GPL(of_dma_simple_xlate);
+
+/**
+ * of_dma_xlate_by_chan_id - Translate dt property to DMA channel by channel id
+ * @dma_spec:  pointer to DMA specifier as found in the device tree
+ * @of_dma:pointer to DMA controller data
+ *
+ * This function can be used as the of xlate callback for DMA driver which 
wants
+ * to match the channel based on the channel id. When using this xlate function
+ * the #dma-cells propety of the DMA controller dt node needs to be set to 1.
+ * The data parameter of of_dma_controller_register must be a pointer to the
+ * dma_device struct the function should match upon.
+ *
+ * Returns pointer to appropriate dma channel on success or NULL on error.
+ */
+struct dma_chan *of_dma_xlate_by_chan_id(struct of_phandle_args *dma_spec,
+struct of_dma *ofdma)
+{
+   struct dma_device *dev = ofdma->of_dma_data;
+   struct dma_chan *chan, *candidate = NULL;
+
+   if (!dev || dma_spec->args_count != 1)
+   return NULL;
+
+   list_for_each_entry(chan, &dev->channels, device_node)
+   if (chan->chan_id == dma_spec->args[0]) {
+   candidate = chan;
+   break;
+   }
+
+   if (!candidate)
+   return NULL;
+
+   return dma_get_slave_channel(candidate);
+}
+EXPORT_SYMBOL_GPL(of_dma_xlate_by_chan_id);
diff --git a/include/linux/of_dma.h b/include/linux/of_dma.h
index ae36298..56bc026 100644
--- a/include/linux/of_dma.h
+++ b/include/linux/of_dma.h
@@ -41,6 +41,8 @@ extern struct dma_chan *of_dma_request_slave_channel(struct 
device_node *np,
 const char *name);
 extern struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_spec,
struct of_dma *ofdma);
+extern struct dma_chan *of_dma_xlate_by_chan_id(struct of_phandle_args 
*dma_spec,
+   struct of_dma *ofdma);
 #else
 static inline int of_dma_controller_register(struct device_node *np,
struct dma_chan *(*of_dma_xlate)
@@ -66,6 +68,8 @@ static inline struct dma_chan *of_dma_simple_xlate(struct 
of_phandle_args *dma_s
return NULL;
 }
 
+#define of_dma_xlate_by_chan_id NULL
+
 #endif
 
 #endif /* __LINUX_OF_DMA_H */
-- 
1.8.4.2

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[PATCH RFC v10 5/6] dma: mpc512x: add device tree binding document

[Alexander Popov]

From: Gerhard Sittig 

introduce a device tree binding document for the MPC512x DMA controller

Signed-off-by: Gerhard Sittig 
[ a13xp0p0...@gmail.com: turn this into a separate patch ]
---
 .../devicetree/bindings/dma/mpc512x-dma.txt| 55 ++
 1 file changed, 55 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/dma/mpc512x-dma.txt

diff --git a/Documentation/devicetree/bindings/dma/mpc512x-dma.txt 
b/Documentation/devicetree/bindings/dma/mpc512x-dma.txt
new file mode 100644
index 000..a4867d5
--- /dev/null
+++ b/Documentation/devicetree/bindings/dma/mpc512x-dma.txt
@@ -0,0 +1,55 @@
+* Freescale MPC512x DMA Controller
+
+The DMA controller in the Freescale MPC512x SoC can move blocks of
+memory contents between memory and peripherals or memory to memory.
+
+Refer to the "Generic DMA Controller and DMA request bindings" description
+in the dma.txt file for a more detailled discussion of the binding.  The
+MPC512x DMA engine binding follows the common scheme, but doesn't provide
+support for the optional channels and requests counters (those values are
+derived from the detected hardware features) and has a fixed client
+specifier length of 1 integer cell (the value is the DMA channel, since
+the DMA controller uses a fixed assignment of request lines per channel).
+
+
+DMA controller node properties:
+
+Required properties:
+- compatible:  should be "fsl,mpc5121-dma"
+- reg: address and size of the DMA controller's register set
+- interrupts:  interrupt spec for the DMA controller
+
+Optional properties:
+- #dma-cells:  must be <1>, describes the number of integer cells
+   needed to specify the 'dmas' property in client nodes,
+   strongly recommended since common client helper code
+   uses this property
+
+Example:
+
+   dma0: dma@14000 {
+   compatible = "fsl,mpc5121-dma";
+   reg = <0x14000 0x1800>;
+   interrupts = <65 0x8>;
+   #dma-cells = <1>;
+   };
+
+
+Client node properties:
+
+Required properties:
+- dmas:list of DMA specifiers, consisting each of a 
handle
+   for the DMA controller and integer cells to specify
+   the channel used within the DMA controller
+- dma-names:   list of identifier strings for the DMA specifiers,
+   client device driver code uses these strings to
+   have DMA channels looked up at the controller
+
+Example:
+
+   sdhc@1500 {
+   compatible = "fsl,mpc5121-sdhc";
+   /* ... */
+   dmas = <&dma0 30>;
+   dma-names = "rx-tx";
+   };
-- 
1.8.4.2

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[PATCH RFC v10 0/6] MPC512x DMA slave s/g support, OF DMA lookup

[Alexander Popov]

 the RAM address or
do increment the peripheral "port's" address is easy with
this implementation; but which options of the common API
should be used for specifying such transfers?
2014/02/13 Gerhard Sittig :
> - The MPC512x DMA completely lacks a binding document, so one
>should get added.
> - The MPC8308 hardware is similar and can re-use the MPC512x
>binding, which should be stated.
> - The Linux implementation currently has no OF based channel
>lookup support, so '#dma-cells' is "a future feature".  I guess
>the binding can and should already discuss the feature,
>regardless of whether all implementations support it.


Alexander Popov (5):
  dma: mpc512x: reorder mpc8308 specific instructions
  dma: mpc512x: add support for peripheral transfers
  dma: mpc512x: fix freeing resources in mpc_dma_probe() and
mpc_dma_remove()
  dma: of: Add common xlate function for matching by channel id
  dma: mpc512x: register for device tree channel lookup

Gerhard Sittig (1):
  dma: mpc512x: add device tree binding document

 .../devicetree/bindings/dma/mpc512x-dma.txt|  55 
 arch/powerpc/boot/dts/mpc5121.dtsi |   1 +
 drivers/dma/mpc512x_dma.c  | 345 ++---
 drivers/dma/of-dma.c   |  35 +++
 include/linux/of_dma.h |   4 +
 5 files changed, 402 insertions(+), 38 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/dma/mpc512x-dma.txt

-- 
1.8.4.2

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[PATCH RFC v9 4/6] dma: of: Add common xlate function for matching by channel id

[Alexander Popov]

This patch adds a new common OF dma xlate callback function which will match a
channel by it's id. The binding expects one integer argument which it will use 
to
lookup the channel by the id.

Unlike of_dma_simple_xlate this function is able to handle a system with
multiple DMA controllers. When registering the of dma provider with
of_dma_controller_register a pointer to the dma_device struct which is
associated with the dt node needs to passed as the data parameter.
New function will use this pointer to match only channels which belong to the
specified DMA controller.

Signed-off-by: Alexander Popov 
---
 drivers/dma/of-dma.c   | 35 +++
 include/linux/of_dma.h |  4 
 2 files changed, 39 insertions(+)

diff --git a/drivers/dma/of-dma.c b/drivers/dma/of-dma.c
index e8fe9dc..d5fbeaa 100644
--- a/drivers/dma/of-dma.c
+++ b/drivers/dma/of-dma.c
@@ -218,3 +218,38 @@ struct dma_chan *of_dma_simple_xlate(struct 
of_phandle_args *dma_spec,
&dma_spec->args[0]);
 }
 EXPORT_SYMBOL_GPL(of_dma_simple_xlate);
+
+/**
+ * of_dma_xlate_by_chan_id - Translate dt property to DMA channel by channel id
+ * @dma_spec:  pointer to DMA specifier as found in the device tree
+ * @of_dma:pointer to DMA controller data
+ *
+ * This function can be used as the of xlate callback for DMA driver which 
wants
+ * to match the channel based on the channel id. When using this xlate function
+ * the #dma-cells propety of the DMA controller dt node needs to be set to 1.
+ * The data parameter of of_dma_controller_register must be a pointer to the
+ * dma_device struct the function should match upon.
+ *
+ * Returns pointer to appropriate dma channel on success or NULL on error.
+ */
+struct dma_chan *of_dma_xlate_by_chan_id(struct of_phandle_args *dma_spec,
+struct of_dma *ofdma)
+{
+   struct dma_device *dev = ofdma->of_dma_data;
+   struct dma_chan *chan, *candidate = NULL;
+
+   if (!dev || dma_spec->args_count != 1)
+   return NULL;
+
+   list_for_each_entry(chan, &dev->channels, device_node)
+   if (chan->chan_id == dma_spec->args[0]) {
+   candidate = chan;
+   break;
+   }
+
+   if (!candidate)
+   return NULL;
+
+   return dma_get_slave_channel(candidate);
+}
+EXPORT_SYMBOL_GPL(of_dma_xlate_by_chan_id);
diff --git a/include/linux/of_dma.h b/include/linux/of_dma.h
index ae36298..56bc026 100644
--- a/include/linux/of_dma.h
+++ b/include/linux/of_dma.h
@@ -41,6 +41,8 @@ extern struct dma_chan *of_dma_request_slave_channel(struct 
device_node *np,
 const char *name);
 extern struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_spec,
struct of_dma *ofdma);
+extern struct dma_chan *of_dma_xlate_by_chan_id(struct of_phandle_args 
*dma_spec,
+   struct of_dma *ofdma);
 #else
 static inline int of_dma_controller_register(struct device_node *np,
struct dma_chan *(*of_dma_xlate)
@@ -66,6 +68,8 @@ static inline struct dma_chan *of_dma_simple_xlate(struct 
of_phandle_args *dma_s
return NULL;
 }
 
+#define of_dma_xlate_by_chan_id NULL
+
 #endif
 
 #endif /* __LINUX_OF_DMA_H */
-- 
1.8.4.2

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[PATCH RFC v9 6/6] dma: mpc512x: register for device tree channel lookup

[Alexander Popov]

Register the controller for device tree based lookup of DMA channels
(non-fatal for backwards compatibility with older device trees) and
provide the '#dma-cells' property in the shared mpc5121.dtsi file

Signed-off-by: Gerhard Sittig 
Signed-off-by: Alexander Popov 
---
 arch/powerpc/boot/dts/mpc5121.dtsi |  1 +
 drivers/dma/mpc512x_dma.c  | 21 ++---
 2 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/boot/dts/mpc5121.dtsi 
b/arch/powerpc/boot/dts/mpc5121.dtsi
index 2c0e155..7f9d14f 100644
--- a/arch/powerpc/boot/dts/mpc5121.dtsi
+++ b/arch/powerpc/boot/dts/mpc5121.dtsi
@@ -498,6 +498,7 @@
compatible = "fsl,mpc5121-dma";
reg = <0x14000 0x1800>;
interrupts = <65 0x8>;
+   #dma-cells = <1>;
};
};
 
diff --git a/drivers/dma/mpc512x_dma.c b/drivers/dma/mpc512x_dma.c
index ff7f678..453b1cb 100644
--- a/drivers/dma/mpc512x_dma.c
+++ b/drivers/dma/mpc512x_dma.c
@@ -52,6 +52,7 @@
 #include 
 #include 
 #include 
+#include 
 #include 
 
 #include 
@@ -1018,11 +1019,23 @@ static int mpc_dma_probe(struct platform_device *op)
/* Register DMA engine */
dev_set_drvdata(dev, mdma);
retval = dma_async_device_register(dma);
-   if (retval) {
-   free_irq(mdma->irq, mdma);
-   irq_dispose_mapping(mdma->irq);
+   if (retval)
+   goto out_irq;
+
+   /* Register with OF helpers for DMA lookups (nonfatal) */
+   if (dev->of_node) {
+   retval = of_dma_controller_register(dev->of_node,
+   of_dma_xlate_by_chan_id, mdma);
+   if (retval)
+   dev_warn(dev, "could not register for OF lookup\n");
}
 
+   return 0;
+
+out_irq:
+   free_irq(mdma->irq, mdma);
+   irq_dispose_mapping(mdma->irq);
+
return retval;
 }
 
@@ -1031,6 +1044,8 @@ static int mpc_dma_remove(struct platform_device *op)
struct device *dev = &op->dev;
struct mpc_dma *mdma = dev_get_drvdata(dev);
 
+   if (dev->of_node)
+   of_dma_controller_free(dev->of_node);
dma_async_device_unregister(&mdma->dma);
free_irq(mdma->irq, mdma);
irq_dispose_mapping(mdma->irq);
-- 
1.8.4.2

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[PATCH RFC v9 5/6] dma: mpc512x: add device tree binding document

[Alexander Popov]

From: Gerhard Sittig 

introduce a device tree binding document for the MPC512x DMA controller

Signed-off-by: Gerhard Sittig 
[ a13xp0p0...@gmail.com: turn this into a separate patch ]
---
 .../devicetree/bindings/dma/mpc512x-dma.txt| 55 ++
 1 file changed, 55 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/dma/mpc512x-dma.txt

diff --git a/Documentation/devicetree/bindings/dma/mpc512x-dma.txt 
b/Documentation/devicetree/bindings/dma/mpc512x-dma.txt
new file mode 100644
index 000..a4867d5
--- /dev/null
+++ b/Documentation/devicetree/bindings/dma/mpc512x-dma.txt
@@ -0,0 +1,55 @@
+* Freescale MPC512x DMA Controller
+
+The DMA controller in the Freescale MPC512x SoC can move blocks of
+memory contents between memory and peripherals or memory to memory.
+
+Refer to the "Generic DMA Controller and DMA request bindings" description
+in the dma.txt file for a more detailled discussion of the binding.  The
+MPC512x DMA engine binding follows the common scheme, but doesn't provide
+support for the optional channels and requests counters (those values are
+derived from the detected hardware features) and has a fixed client
+specifier length of 1 integer cell (the value is the DMA channel, since
+the DMA controller uses a fixed assignment of request lines per channel).
+
+
+DMA controller node properties:
+
+Required properties:
+- compatible:  should be "fsl,mpc5121-dma"
+- reg: address and size of the DMA controller's register set
+- interrupts:  interrupt spec for the DMA controller
+
+Optional properties:
+- #dma-cells:  must be <1>, describes the number of integer cells
+   needed to specify the 'dmas' property in client nodes,
+   strongly recommended since common client helper code
+   uses this property
+
+Example:
+
+   dma0: dma@14000 {
+   compatible = "fsl,mpc5121-dma";
+   reg = <0x14000 0x1800>;
+   interrupts = <65 0x8>;
+   #dma-cells = <1>;
+   };
+
+
+Client node properties:
+
+Required properties:
+- dmas:list of DMA specifiers, consisting each of a 
handle
+   for the DMA controller and integer cells to specify
+   the channel used within the DMA controller
+- dma-names:   list of identifier strings for the DMA specifiers,
+   client device driver code uses these strings to
+   have DMA channels looked up at the controller
+
+Example:
+
+   sdhc@1500 {
+   compatible = "fsl,mpc5121-sdhc";
+   /* ... */
+   dmas = <&dma0 30>;
+   dma-names = "rx-tx";
+   };
-- 
1.8.4.2

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[PATCH RFC v9 0/6] MPC512x DMA slave s/g support, OF DMA lookup

[Alexander Popov]

2013/7/14 Gerhard Sittig :
> this series
> - introduces slave s/g support (that's support for DMA transfers which
>involve peripherals in contrast to mem-to-mem transfers)
> - adds device tree based lookup support for DMA channels
> - combines floating patches and related feedback which already covered
>several aspects of what the suggested LPB driver needs, to demonstrate
>how integration might be done
> - carries Q&D SD card support to enable another DMA client during test,
>while this patch needs to get dropped upon pickup

Changes in v2:
> - re-order mpc8308 related code paths for improved readability, no
>change in behaviour, introduction of symbolic channel names here
>already
> - squash 'execute() start condition' and 'terminate all' into the
>introduction of 'slave s/g prep' and 'device control' support; refuse
>s/g lists with more than one item since slave support is operational
>yet proper s/g support is missing (can get addressed later)
> - always start transfers from software on MPC8308 as there are no
>external request lines for peripheral flow control
> - drop dt-bindings header file and symbolic channel names in OF nodes

Changes in v3 and v4:
 Part 1/5:
 - use #define instead of enum since individual channels don't require
special handling.
 Part 2/5:
 - add a flag "will_access_peripheral" to DMA transfer descriptor
according recommendations of Gerhard Sittig.
This flag is set in mpc_dma_prep_memcpy() and mpc_dma_prep_slave_sg()
and is evaluated in mpc_dma_execute() to choose a type of start for
the transfer.
 - prevent descriptors of transfers which involve peripherals from
being chained together;
each of such transfers needs hardware initiated start.
 - add locking while working with struct mpc_dma_chan
according recommendations of Lars-Peter Clausen.
 - remove default nbytes value. Client kernel modules must set
src_maxburst and dst_maxburst fields of struct dma_slave_config 
(dmaengine.h).

Changes in v5:
 Part 2/5:
 - add and improve comments;
 - improve the code moving transfer descriptors from 'queued' to 'active' list
in mpc_dma_execute();
 - allow mpc_dma_prep_slave_sg() to run with non-empty 'active' list;
 - take 'mdesc' back to 'free' list in case of error in mpc_dma_prep_slave_sg();
 - improve checks of the transfer parameters;
 - provide the default value for 'maxburst' in mpc_dma_device_control().

Changes in v6:
 Part 2/5:
 - remove doubtful comment;
 - fix coding style issues;
 - set default value for 'maxburst' to 1 which applies to most cases;
 Part 3/5:
 - use dma_get_slave_channel() instead of dma_request_channel()
in new function of_dma_xlate_by_chan_id() according recommendations of
Arnd Bergmann;
 Part 4/5:
 - set DMA_PRIVATE flag for MPC512x DMA controller since its driver relies on
of_dma_xlate_by_chan_id() which doesn't use dma_request_channel()
any more; (removed in v7)
 - resolve little patch conflict;
 Part 5/5:
 - resolve little patch conflict;

Changes in v7:
 Part 2:
 - improve comment;
 Part 4:
 - split in two separate patches. Part 4/6 contains device tree
binding document and in part 5/6 MPC512x DMA controller is registered
for device tree channel lookup;
 - remove setting DMA_PRIVATE flag for MPC512x DMA controller from part 5/6;

Changes in v8:
 Part 2:
 - improve comments;
 - fix style issues;
 Part 6:
 - remove since it has become obsolete;

Changes in v9:
 A new patch (part 3/6) is added to this series according the
   feedback of Andy Shevchenko.
 Part 2/6:
 - keep style of the comments;
 - use is_slave_direction() instead of manual checks;
 - remove redundant else branches of the conditions;
 - make mpc_dma_device_control() return -ENXIO for unknown command;
 Part 6/6:
 - change according the new part 3/6;
 - fix style issues;

> known issues:
> - it's yet to get confirmed whether MPC8308 can use slave support or
>whether the DMA controller's driver shall actively reject it, the
>information that's available so far suggests that peripheral transfers
>to IP bus attached I/O is useful and shall not get blocked right away
 - adding support for transfers which don't increment the RAM address or
do increment the peripheral "port's" address is easy with
this implementation; but which options of the common API
should be used for specifying such transfers?
2014/02/13 Gerhard Sittig :
> - The MPC512x DMA completely lacks a binding document, so one
>should get added.
> - The MPC8308 hardware is similar and can re-use the MPC512x
>binding, which should be stated.
> - The Linux implementation currently has no OF based channel
>lookup support, so '#dm

Re: [PATCH RFC v8 5/5] dma: mpc512x: register for device tree channel lookup

[Alexander Popov]

Hello Andy.

2014-02-24 17:08 GMT+04:00 Andy Shevchenko :
> On Mon, 2014-02-24 at 15:09 +0400, Alexander Popov wrote:
>> @@ -1018,11 +1019,23 @@ static int mpc_dma_probe(struct platform_device *op)
>>   /* Register DMA engine */
>>   dev_set_drvdata(dev, mdma);
>>   retval = dma_async_device_register(dma);
>> - if (retval) {
>> - devm_free_irq(dev, mdma->irq, mdma);
>> - irq_dispose_mapping(mdma->irq);
>> + if (retval)
>> + goto out_irq;
>> +
>> + /* register with OF helpers for DMA lookups (nonfatal) */
>> + if (dev->of_node) {
>> + retval = of_dma_controller_register(dev->of_node,
>> + of_dma_xlate_by_chan_id,
>> + mdma);
>> + if (retval)
>> + dev_warn(dev, "could not register for OF lookup\n");
>>   }
>>
>> + return 0;
>> +
>> +out_irq:
>> + devm_free_irq(dev, mdma->irq, mdma);
>
> Something wrong either with devm_request_irq() or you don't need to call
> devm_free_irq() explicitly. Once we already try to discuss this earlier
> in this mailing list with Lars-Peter(?), though there were no solution
> how to keep devm_*_irq usability.

Thanks, I've read this discussion. It seems that the current code doesn't do
anything bad, though devm_request_irq() and devm_free_irq() can be changed
to request_irq() and free_irq() accordingly. Do you think it's worth being done
in a separate patch in this series?

>> + irq_dispose_mapping(mdma->irq);
>>   return retval;
>>  }
>>
>> @@ -1031,6 +1044,8 @@ static int mpc_dma_remove(struct platform_device *op)
>>   struct device *dev = &op->dev;
>>   struct mpc_dma *mdma = dev_get_drvdata(dev);
>>
>> + if (dev->of_node)
>> + of_dma_controller_free(dev->of_node);
>>   dma_async_device_unregister(&mdma->dma);
>>   devm_free_irq(dev, mdma->irq, mdma);
>>   irq_dispose_mapping(mdma->irq);

Best regards,
Alexander
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[PATCH RFC v8 3/5] dma: of: Add common xlate function for matching by channel id

[Alexander Popov]

This patch adds a new common OF dma xlate callback function which will match a
channel by it's id. The binding expects one integer argument which it will use 
to
lookup the channel by the id.

Unlike of_dma_simple_xlate this function is able to handle a system with
multiple DMA controllers. When registering the of dma provider with
of_dma_controller_register a pointer to the dma_device struct which is
associated with the dt node needs to passed as the data parameter.
New function will use this pointer to match only channels which belong to the
specified DMA controller.

Signed-off-by: Alexander Popov 
---
 drivers/dma/of-dma.c   | 35 +++
 include/linux/of_dma.h |  4 
 2 files changed, 39 insertions(+)

diff --git a/drivers/dma/of-dma.c b/drivers/dma/of-dma.c
index e8fe9dc..d5fbeaa 100644
--- a/drivers/dma/of-dma.c
+++ b/drivers/dma/of-dma.c
@@ -218,3 +218,38 @@ struct dma_chan *of_dma_simple_xlate(struct 
of_phandle_args *dma_spec,
&dma_spec->args[0]);
 }
 EXPORT_SYMBOL_GPL(of_dma_simple_xlate);
+
+/**
+ * of_dma_xlate_by_chan_id - Translate dt property to DMA channel by channel id
+ * @dma_spec:  pointer to DMA specifier as found in the device tree
+ * @of_dma:pointer to DMA controller data
+ *
+ * This function can be used as the of xlate callback for DMA driver which 
wants
+ * to match the channel based on the channel id. When using this xlate function
+ * the #dma-cells propety of the DMA controller dt node needs to be set to 1.
+ * The data parameter of of_dma_controller_register must be a pointer to the
+ * dma_device struct the function should match upon.
+ *
+ * Returns pointer to appropriate dma channel on success or NULL on error.
+ */
+struct dma_chan *of_dma_xlate_by_chan_id(struct of_phandle_args *dma_spec,
+struct of_dma *ofdma)
+{
+   struct dma_device *dev = ofdma->of_dma_data;
+   struct dma_chan *chan, *candidate = NULL;
+
+   if (!dev || dma_spec->args_count != 1)
+   return NULL;
+
+   list_for_each_entry(chan, &dev->channels, device_node)
+   if (chan->chan_id == dma_spec->args[0]) {
+   candidate = chan;
+   break;
+   }
+
+   if (!candidate)
+   return NULL;
+
+   return dma_get_slave_channel(candidate);
+}
+EXPORT_SYMBOL_GPL(of_dma_xlate_by_chan_id);
diff --git a/include/linux/of_dma.h b/include/linux/of_dma.h
index ae36298..56bc026 100644
--- a/include/linux/of_dma.h
+++ b/include/linux/of_dma.h
@@ -41,6 +41,8 @@ extern struct dma_chan *of_dma_request_slave_channel(struct 
device_node *np,
 const char *name);
 extern struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_spec,
struct of_dma *ofdma);
+extern struct dma_chan *of_dma_xlate_by_chan_id(struct of_phandle_args 
*dma_spec,
+   struct of_dma *ofdma);
 #else
 static inline int of_dma_controller_register(struct device_node *np,
struct dma_chan *(*of_dma_xlate)
@@ -66,6 +68,8 @@ static inline struct dma_chan *of_dma_simple_xlate(struct 
of_phandle_args *dma_s
return NULL;
 }
 
+#define of_dma_xlate_by_chan_id NULL
+
 #endif
 
 #endif /* __LINUX_OF_DMA_H */
-- 
1.8.4.2

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[PATCH RFC v8 4/5] dma: mpc512x: add device tree binding document

[Alexander Popov]

From: Gerhard Sittig 

introduce a device tree binding document for the MPC512x DMA controller

Signed-off-by: Gerhard Sittig 
[ a13xp0p0...@gmail.com: turn this into a separate patch ]
---
 .../devicetree/bindings/dma/mpc512x-dma.txt| 55 ++
 1 file changed, 55 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/dma/mpc512x-dma.txt

diff --git a/Documentation/devicetree/bindings/dma/mpc512x-dma.txt 
b/Documentation/devicetree/bindings/dma/mpc512x-dma.txt
new file mode 100644
index 000..a4867d5
--- /dev/null
+++ b/Documentation/devicetree/bindings/dma/mpc512x-dma.txt
@@ -0,0 +1,55 @@
+* Freescale MPC512x DMA Controller
+
+The DMA controller in the Freescale MPC512x SoC can move blocks of
+memory contents between memory and peripherals or memory to memory.
+
+Refer to the "Generic DMA Controller and DMA request bindings" description
+in the dma.txt file for a more detailled discussion of the binding.  The
+MPC512x DMA engine binding follows the common scheme, but doesn't provide
+support for the optional channels and requests counters (those values are
+derived from the detected hardware features) and has a fixed client
+specifier length of 1 integer cell (the value is the DMA channel, since
+the DMA controller uses a fixed assignment of request lines per channel).
+
+
+DMA controller node properties:
+
+Required properties:
+- compatible:  should be "fsl,mpc5121-dma"
+- reg: address and size of the DMA controller's register set
+- interrupts:  interrupt spec for the DMA controller
+
+Optional properties:
+- #dma-cells:  must be <1>, describes the number of integer cells
+   needed to specify the 'dmas' property in client nodes,
+   strongly recommended since common client helper code
+   uses this property
+
+Example:
+
+   dma0: dma@14000 {
+   compatible = "fsl,mpc5121-dma";
+   reg = <0x14000 0x1800>;
+   interrupts = <65 0x8>;
+   #dma-cells = <1>;
+   };
+
+
+Client node properties:
+
+Required properties:
+- dmas:list of DMA specifiers, consisting each of a 
handle
+   for the DMA controller and integer cells to specify
+   the channel used within the DMA controller
+- dma-names:   list of identifier strings for the DMA specifiers,
+   client device driver code uses these strings to
+   have DMA channels looked up at the controller
+
+Example:
+
+   sdhc@1500 {
+   compatible = "fsl,mpc5121-sdhc";
+   /* ... */
+   dmas = <&dma0 30>;
+   dma-names = "rx-tx";
+   };
-- 
1.8.4.2

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[PATCH RFC v8 5/5] dma: mpc512x: register for device tree channel lookup

[Alexander Popov]

From: Gerhard Sittig 

register the controller for device tree based lookup of DMA channels
(non-fatal for backwards compatibility with older device trees) and
provide the '#dma-cells' property in the shared mpc5121.dtsi file

Signed-off-by: Gerhard Sittig 
[ a13xp0p0...@gmail.com: resolve little patch conflict and put
  MPC512x DMA controller bindings document to a separate patch ]
---
 arch/powerpc/boot/dts/mpc5121.dtsi |  1 +
 drivers/dma/mpc512x_dma.c  | 21 ++---
 2 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/boot/dts/mpc5121.dtsi 
b/arch/powerpc/boot/dts/mpc5121.dtsi
index 2c0e155..7f9d14f 100644
--- a/arch/powerpc/boot/dts/mpc5121.dtsi
+++ b/arch/powerpc/boot/dts/mpc5121.dtsi
@@ -498,6 +498,7 @@
compatible = "fsl,mpc5121-dma";
reg = <0x14000 0x1800>;
interrupts = <65 0x8>;
+   #dma-cells = <1>;
};
};
 
diff --git a/drivers/dma/mpc512x_dma.c b/drivers/dma/mpc512x_dma.c
index 8f504cb..d9f8740 100644
--- a/drivers/dma/mpc512x_dma.c
+++ b/drivers/dma/mpc512x_dma.c
@@ -52,6 +52,7 @@
 #include 
 #include 
 #include 
+#include 
 #include 
 
 #include 
@@ -1018,11 +1019,23 @@ static int mpc_dma_probe(struct platform_device *op)
/* Register DMA engine */
dev_set_drvdata(dev, mdma);
retval = dma_async_device_register(dma);
-   if (retval) {
-   devm_free_irq(dev, mdma->irq, mdma);
-   irq_dispose_mapping(mdma->irq);
+   if (retval)
+   goto out_irq;
+
+   /* register with OF helpers for DMA lookups (nonfatal) */
+   if (dev->of_node) {
+   retval = of_dma_controller_register(dev->of_node,
+   of_dma_xlate_by_chan_id,
+   mdma);
+   if (retval)
+   dev_warn(dev, "could not register for OF lookup\n");
}
 
+   return 0;
+
+out_irq:
+   devm_free_irq(dev, mdma->irq, mdma);
+   irq_dispose_mapping(mdma->irq);
return retval;
 }
 
@@ -1031,6 +1044,8 @@ static int mpc_dma_remove(struct platform_device *op)
struct device *dev = &op->dev;
struct mpc_dma *mdma = dev_get_drvdata(dev);
 
+   if (dev->of_node)
+   of_dma_controller_free(dev->of_node);
dma_async_device_unregister(&mdma->dma);
devm_free_irq(dev, mdma->irq, mdma);
irq_dispose_mapping(mdma->irq);
-- 
1.8.4.2

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[PATCH RFC v8 0/5] MPC512x DMA slave s/g support, OF DMA lookup

[Alexander Popov]

2013/7/14 Gerhard Sittig :
> this series
> - introduces slave s/g support (that's support for DMA transfers which
>involve peripherals in contrast to mem-to-mem transfers)
> - adds device tree based lookup support for DMA channels
> - combines floating patches and related feedback which already covered
>several aspects of what the suggested LPB driver needs, to demonstrate
>how integration might be done
> - carries Q&D SD card support to enable another DMA client during test,
>while this patch needs to get dropped upon pickup

Changes in v2:
> - re-order mpc8308 related code paths for improved readability, no
>change in behaviour, introduction of symbolic channel names here
>already
> - squash 'execute() start condition' and 'terminate all' into the
>introduction of 'slave s/g prep' and 'device control' support; refuse
>s/g lists with more than one item since slave support is operational
>yet proper s/g support is missing (can get addressed later)
> - always start transfers from software on MPC8308 as there are no
>external request lines for peripheral flow control
> - drop dt-bindings header file and symbolic channel names in OF nodes

Changes in v3 and v4:
 Part 1/5:
 - use #define instead of enum since individual channels don't require
special handling.
 Part 2/5:
 - add a flag "will_access_peripheral" to DMA transfer descriptor
according recommendations of Gerhard Sittig.
This flag is set in mpc_dma_prep_memcpy() and mpc_dma_prep_slave_sg()
and is evaluated in mpc_dma_execute() to choose a type of start for
the transfer.
 - prevent descriptors of transfers which involve peripherals from
being chained together;
each of such transfers needs hardware initiated start.
 - add locking while working with struct mpc_dma_chan
according recommendations of Lars-Peter Clausen.
 - remove default nbytes value. Client kernel modules must set
src_maxburst and dst_maxburst fields of struct dma_slave_config 
(dmaengine.h).

Changes in v5:
 Part 2/5:
 - add and improve comments;
 - improve the code moving transfer descriptors from 'queued' to 'active' list
in mpc_dma_execute();
 - allow mpc_dma_prep_slave_sg() to run with non-empty 'active' list;
 - take 'mdesc' back to 'free' list in case of error in mpc_dma_prep_slave_sg();
 - improve checks of the transfer parameters;
 - provide the default value for 'maxburst' in mpc_dma_device_control().

Changes in v6:
 Part 2/5:
 - remove doubtful comment;
 - fix coding style issues;
 - set default value for 'maxburst' to 1 which applies to most cases;
 Part 3/5:
 - use dma_get_slave_channel() instead of dma_request_channel()
in new function of_dma_xlate_by_chan_id() according recommendations of
Arnd Bergmann;
 Part 4/5:
 - set DMA_PRIVATE flag for MPC512x DMA controller since its driver relies on
of_dma_xlate_by_chan_id() which doesn't use dma_request_channel()
any more; (removed in v7)
 - resolve little patch conflict;
 Part 5/5:
 - resolve little patch conflict;

Changes in v7:
 Part 2:
 - improve comment;
 Part 4:
 - split in two separate patches. Part 4/6 contains device tree
binding document and in part 5/6 MPC512x DMA controller is registered
for device tree channel lookup;
 - remove setting DMA_PRIVATE flag for MPC512x DMA controller from part 5/6;

Changes in v8:
 Part 2:
 - improve comments;
 - fix style issues;
 Part 6:
 - remove since it has become obsolete;

> known issues:
> - it's yet to get confirmed whether MPC8308 can use slave support or
>whether the DMA controller's driver shall actively reject it, the
>information that's available so far suggests that peripheral transfers
>to IP bus attached I/O is useful and shall not get blocked right away
 - adding support for transfers which don't increment the RAM address or
do increment the peripheral "port's" address is easy with
this implementation; but which options of the common API
should be used for specifying such transfers?
2014/02/13 Gerhard Sittig :
> - The MPC512x DMA completely lacks a binding document, so one
>should get added.
> - The MPC8308 hardware is similar and can re-use the MPC512x
>binding, which should be stated.
> - The Linux implementation currently has no OF based channel
>lookup support, so '#dma-cells' is "a future feature".  I guess
>the binding can and should already discuss the feature,
>regardless of whether all implementations support it.


Alexander Popov (3):
  dma: mpc512x: reorder mpc8308 specific instructions
  dma: mpc512x: add support for peripheral transfers
  dma: of: Add common xlate function for matching by channel id

Gerhard Sittig (

Re: [PATCH RFC v7 0/6] MPC512x DMA slave s/g support, OF DMA lookup

[Alexander Popov]

Hello, Gerhard

2014-02-13 4:32 GMT+04:00 Gerhard Sittig :
> For some reason you have kept the DMA maintainers, but dropped
> the dmaengine ML from Cc: -- was this intentional, given that the
> series is specifically about DMA and you want to get feedback?
No, it was not done by intention, I'll fix that in the new version of the
series.

> And you may want to help DT people by not sending purely Linux
> implementation related stuff to them (they already are drinking
> from the firehose).  DT reviewers are foremost interested in
> bindings and policy and remaining OS agnostic, and leave
> mechanical .dts file updates to subsystem maintainers.
Do you mean I should better Cc to devicetree@vger.kernel.org
only parts 3, 4 and 5 of this series? How about cover letter?

Thank you.

Alexander
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[PATCH RFC v7 1/6] dma: mpc512x: reorder mpc8308 specific instructions

[Alexander Popov]

Concentrate the specific code for MPC8308 in the 'if' branch
and handle MPC512x in the 'else' branch.
This modification only reorders instructions but doesn't change behaviour.

Signed-off-by: Alexander Popov 
Acked-by: Anatolij Gustschin 
Acked-by: Gerhard Sittig 
---
 drivers/dma/mpc512x_dma.c | 42 +-
 1 file changed, 25 insertions(+), 17 deletions(-)

diff --git a/drivers/dma/mpc512x_dma.c b/drivers/dma/mpc512x_dma.c
index 448750d..2ce248b 100644
--- a/drivers/dma/mpc512x_dma.c
+++ b/drivers/dma/mpc512x_dma.c
@@ -52,9 +52,17 @@
 #define MPC_DMA_DESCRIPTORS64
 
 /* Macro definitions */
-#define MPC_DMA_CHANNELS   64
 #define MPC_DMA_TCD_OFFSET 0x1000
 
+/*
+ * Maximum channel counts for individual hardware variants
+ * and the maximum channel count over all supported controllers,
+ * used for data structure size
+ */
+#define MPC8308_DMACHAN_MAX16
+#define MPC512x_DMACHAN_MAX64
+#define MPC_DMA_CHANNELS   64
+
 /* Arbitration mode of group and channel */
 #define MPC_DMA_DMACR_EDCG (1 << 31)
 #define MPC_DMA_DMACR_ERGA (1 << 3)
@@ -710,10 +718,10 @@ static int mpc_dma_probe(struct platform_device *op)
 
dma = &mdma->dma;
dma->dev = dev;
-   if (!mdma->is_mpc8308)
-   dma->chancnt = MPC_DMA_CHANNELS;
+   if (mdma->is_mpc8308)
+   dma->chancnt = MPC8308_DMACHAN_MAX;
else
-   dma->chancnt = 16; /* MPC8308 DMA has only 16 channels */
+   dma->chancnt = MPC512x_DMACHAN_MAX;
dma->device_alloc_chan_resources = mpc_dma_alloc_chan_resources;
dma->device_free_chan_resources = mpc_dma_free_chan_resources;
dma->device_issue_pending = mpc_dma_issue_pending;
@@ -747,7 +755,19 @@ static int mpc_dma_probe(struct platform_device *op)
 * - Round-robin group arbitration,
 * - Round-robin channel arbitration.
 */
-   if (!mdma->is_mpc8308) {
+   if (mdma->is_mpc8308) {
+   /* MPC8308 has 16 channels and lacks some registers */
+   out_be32(&mdma->regs->dmacr, MPC_DMA_DMACR_ERCA);
+
+   /* enable snooping */
+   out_be32(&mdma->regs->dmagpor, MPC_DMA_DMAGPOR_SNOOP_ENABLE);
+   /* Disable error interrupts */
+   out_be32(&mdma->regs->dmaeeil, 0);
+
+   /* Clear interrupts status */
+   out_be32(&mdma->regs->dmaintl, 0x);
+   out_be32(&mdma->regs->dmaerrl, 0x);
+   } else {
out_be32(&mdma->regs->dmacr, MPC_DMA_DMACR_EDCG |
MPC_DMA_DMACR_ERGA | 
MPC_DMA_DMACR_ERCA);
 
@@ -768,18 +788,6 @@ static int mpc_dma_probe(struct platform_device *op)
/* Route interrupts to IPIC */
out_be32(&mdma->regs->dmaihsa, 0);
out_be32(&mdma->regs->dmailsa, 0);
-   } else {
-   /* MPC8308 has 16 channels and lacks some registers */
-   out_be32(&mdma->regs->dmacr, MPC_DMA_DMACR_ERCA);
-
-   /* enable snooping */
-   out_be32(&mdma->regs->dmagpor, MPC_DMA_DMAGPOR_SNOOP_ENABLE);
-   /* Disable error interrupts */
-   out_be32(&mdma->regs->dmaeeil, 0);
-
-   /* Clear interrupts status */
-   out_be32(&mdma->regs->dmaintl, 0x);
-   out_be32(&mdma->regs->dmaerrl, 0x);
}
 
/* Register DMA engine */
-- 
1.8.4.2

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[PATCH RFC v7 4/6] dma: mpc512x: add device tree binding document

[Alexander Popov]

From: Gerhard Sittig 

introduce a device tree binding document for the MPC512x DMA controller

Signed-off-by: Gerhard Sittig 
[ a13xp0p0...@gmail.com: turn this into a separate patch ]
---
 .../devicetree/bindings/dma/mpc512x-dma.txt| 55 ++
 1 file changed, 55 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/dma/mpc512x-dma.txt

diff --git a/Documentation/devicetree/bindings/dma/mpc512x-dma.txt 
b/Documentation/devicetree/bindings/dma/mpc512x-dma.txt
new file mode 100644
index 000..a4867d5
--- /dev/null
+++ b/Documentation/devicetree/bindings/dma/mpc512x-dma.txt
@@ -0,0 +1,55 @@
+* Freescale MPC512x DMA Controller
+
+The DMA controller in the Freescale MPC512x SoC can move blocks of
+memory contents between memory and peripherals or memory to memory.
+
+Refer to the "Generic DMA Controller and DMA request bindings" description
+in the dma.txt file for a more detailled discussion of the binding.  The
+MPC512x DMA engine binding follows the common scheme, but doesn't provide
+support for the optional channels and requests counters (those values are
+derived from the detected hardware features) and has a fixed client
+specifier length of 1 integer cell (the value is the DMA channel, since
+the DMA controller uses a fixed assignment of request lines per channel).
+
+
+DMA controller node properties:
+
+Required properties:
+- compatible:  should be "fsl,mpc5121-dma"
+- reg: address and size of the DMA controller's register set
+- interrupts:  interrupt spec for the DMA controller
+
+Optional properties:
+- #dma-cells:  must be <1>, describes the number of integer cells
+   needed to specify the 'dmas' property in client nodes,
+   strongly recommended since common client helper code
+   uses this property
+
+Example:
+
+   dma0: dma@14000 {
+   compatible = "fsl,mpc5121-dma";
+   reg = <0x14000 0x1800>;
+   interrupts = <65 0x8>;
+   #dma-cells = <1>;
+   };
+
+
+Client node properties:
+
+Required properties:
+- dmas:list of DMA specifiers, consisting each of a 
handle
+   for the DMA controller and integer cells to specify
+   the channel used within the DMA controller
+- dma-names:   list of identifier strings for the DMA specifiers,
+   client device driver code uses these strings to
+   have DMA channels looked up at the controller
+
+Example:
+
+   sdhc@1500 {
+   compatible = "fsl,mpc5121-sdhc";
+   /* ... */
+   dmas = <&dma0 30>;
+   dma-names = "rx-tx";
+   };
-- 
1.8.4.2

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[PATCH RFC v7 3/6] dma: of: Add common xlate function for matching by channel id

[Alexander Popov]

This patch adds a new common OF dma xlate callback function which will match a
channel by it's id. The binding expects one integer argument which it will use 
to
lookup the channel by the id.

Unlike of_dma_simple_xlate this function is able to handle a system with
multiple DMA controllers. When registering the of dma provider with
of_dma_controller_register a pointer to the dma_device struct which is
associated with the dt node needs to passed as the data parameter.
New function will use this pointer to match only channels which belong to the
specified DMA controller.

Signed-off-by: Alexander Popov 
---
 drivers/dma/of-dma.c   | 35 +++
 include/linux/of_dma.h |  4 
 2 files changed, 39 insertions(+)

diff --git a/drivers/dma/of-dma.c b/drivers/dma/of-dma.c
index e8fe9dc..d5fbeaa 100644
--- a/drivers/dma/of-dma.c
+++ b/drivers/dma/of-dma.c
@@ -218,3 +218,38 @@ struct dma_chan *of_dma_simple_xlate(struct 
of_phandle_args *dma_spec,
&dma_spec->args[0]);
 }
 EXPORT_SYMBOL_GPL(of_dma_simple_xlate);
+
+/**
+ * of_dma_xlate_by_chan_id - Translate dt property to DMA channel by channel id
+ * @dma_spec:  pointer to DMA specifier as found in the device tree
+ * @of_dma:pointer to DMA controller data
+ *
+ * This function can be used as the of xlate callback for DMA driver which 
wants
+ * to match the channel based on the channel id. When using this xlate function
+ * the #dma-cells propety of the DMA controller dt node needs to be set to 1.
+ * The data parameter of of_dma_controller_register must be a pointer to the
+ * dma_device struct the function should match upon.
+ *
+ * Returns pointer to appropriate dma channel on success or NULL on error.
+ */
+struct dma_chan *of_dma_xlate_by_chan_id(struct of_phandle_args *dma_spec,
+struct of_dma *ofdma)
+{
+   struct dma_device *dev = ofdma->of_dma_data;
+   struct dma_chan *chan, *candidate = NULL;
+
+   if (!dev || dma_spec->args_count != 1)
+   return NULL;
+
+   list_for_each_entry(chan, &dev->channels, device_node)
+   if (chan->chan_id == dma_spec->args[0]) {
+   candidate = chan;
+   break;
+   }
+
+   if (!candidate)
+   return NULL;
+
+   return dma_get_slave_channel(candidate);
+}
+EXPORT_SYMBOL_GPL(of_dma_xlate_by_chan_id);
diff --git a/include/linux/of_dma.h b/include/linux/of_dma.h
index ae36298..56bc026 100644
--- a/include/linux/of_dma.h
+++ b/include/linux/of_dma.h
@@ -41,6 +41,8 @@ extern struct dma_chan *of_dma_request_slave_channel(struct 
device_node *np,
 const char *name);
 extern struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_spec,
struct of_dma *ofdma);
+extern struct dma_chan *of_dma_xlate_by_chan_id(struct of_phandle_args 
*dma_spec,
+   struct of_dma *ofdma);
 #else
 static inline int of_dma_controller_register(struct device_node *np,
struct dma_chan *(*of_dma_xlate)
@@ -66,6 +68,8 @@ static inline struct dma_chan *of_dma_simple_xlate(struct 
of_phandle_args *dma_s
return NULL;
 }
 
+#define of_dma_xlate_by_chan_id NULL
+
 #endif
 
 #endif /* __LINUX_OF_DMA_H */
-- 
1.8.4.2

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[PATCH RFC v7 2/6] dma: mpc512x: add support for peripheral transfers

[Alexander Popov]

Introduce support for slave s/g transfer preparation and the associated
device control callback in the MPC512x DMA controller driver, which adds
support for data transfers between memory and peripheral I/O to the
previously supported mem-to-mem transfers.

Signed-off-by: Alexander Popov 
---
 drivers/dma/mpc512x_dma.c | 230 +-
 1 file changed, 225 insertions(+), 5 deletions(-)

diff --git a/drivers/dma/mpc512x_dma.c b/drivers/dma/mpc512x_dma.c
index 2ce248b..b978ef1 100644
--- a/drivers/dma/mpc512x_dma.c
+++ b/drivers/dma/mpc512x_dma.c
@@ -2,6 +2,7 @@
  * Copyright (C) Freescale Semicondutor, Inc. 2007, 2008.
  * Copyright (C) Semihalf 2009
  * Copyright (C) Ilya Yanok, Emcraft Systems 2010
+ * Copyright (C) Alexander Popov, Promcontroller 2013
  *
  * Written by Piotr Ziecik . Hardware description
  * (defines, structures and comments) was taken from MPC5121 DMA driver
@@ -29,8 +30,15 @@
  */
 
 /*
- * This is initial version of MPC5121 DMA driver. Only memory to memory
- * transfers are supported (tested using dmatest module).
+ * MPC512x and MPC8308 DMA driver. It supports
+ * memory to memory data transfers (tested using dmatest module) and
+ * data transfers between memory and peripheral I/O memory
+ * by means of slave s/g with these limitations:
+ * - chunked transfers (transfers with more than one part) are refused
+ * as long as proper support for scatter/gather is missing;
+ * - transfers on MPC8308 always start from software as this SoC appears
+ * not to have external request lines for peripheral flow control;
+ * - minimal memory <-> I/O memory transfer size is 4 bytes.
  */
 
 #include 
@@ -189,6 +197,7 @@ struct mpc_dma_desc {
dma_addr_t  tcd_paddr;
int error;
struct list_headnode;
+   int will_access_peripheral;
 };
 
 struct mpc_dma_chan {
@@ -201,6 +210,10 @@ struct mpc_dma_chan {
struct mpc_dma_tcd  *tcd;
dma_addr_t  tcd_paddr;
 
+   /* Settings for access to peripheral FIFO */
+   dma_addr_t  per_paddr;  /* FIFO address */
+   u32 tcd_nunits;
+
/* Lock for this structure */
spinlock_t  lock;
 };
@@ -251,8 +264,21 @@ static void mpc_dma_execute(struct mpc_dma_chan *mchan)
struct mpc_dma_desc *mdesc;
int cid = mchan->chan.chan_id;
 
-   /* Move all queued descriptors to active list */
-   list_splice_tail_init(&mchan->queued, &mchan->active);
+   while (!list_empty(&mchan->queued)) {
+   mdesc = list_first_entry(&mchan->queued,
+   struct mpc_dma_desc, node);
+
+   /* Grab either several mem-to-mem transfer descriptors
+* or one peripheral transfer descriptor,
+* don't mix mem-to-mem and peripheral transfer descriptors
+* within the same 'active' list. */
+   if (mdesc->will_access_peripheral) {
+   if (list_empty(&mchan->active))
+   list_move_tail(&mdesc->node, &mchan->active);
+   break;
+   } else
+   list_move_tail(&mdesc->node, &mchan->active);
+   }
 
/* Chain descriptors into one transaction */
list_for_each_entry(mdesc, &mchan->active, node) {
@@ -278,7 +304,17 @@ static void mpc_dma_execute(struct mpc_dma_chan *mchan)
 
if (first != prev)
mdma->tcd[cid].e_sg = 1;
-   out_8(&mdma->regs->dmassrt, cid);
+
+   if (mdma->is_mpc8308) {
+   /* MPC8308, no request lines, software initiated start */
+   out_8(&mdma->regs->dmassrt, cid);
+   } else if (first->will_access_peripheral) {
+   /* peripherals involved, start by external request signal */
+   out_8(&mdma->regs->dmaserq, cid);
+   } else {
+   /* memory to memory transfer, software initiated start */
+   out_8(&mdma->regs->dmassrt, cid);
+   }
 }
 
 /* Handle interrupt on one half of DMA controller (32 channels) */
@@ -596,6 +632,7 @@ mpc_dma_prep_memcpy(struct dma_chan *chan, dma_addr_t dst, 
dma_addr_t src,
}
 
mdesc->error = 0;
+   mdesc->will_access_peripheral = 0;
tcd = mdesc->tcd;
 
/* Prepare Transfer Control Descriptor for this transaction */
@@ -643,6 +680,186 @@ mpc_dma_prep_memcpy(struct dma_chan *chan, dma_addr_t 
dst, dma_addr_t src,
return &mdesc->desc;
 }
 
+static struct dma_async_tx_descriptor *
+mpc_dma_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
+   unsigned int sg_len, enum dma_transfer

[PATCH RFC v7 6/6] HACK mmc: mxcmmc: enable clocks for the MPC512x

[Alexander Popov]

From: Gerhard Sittig 

Q&D HACK to enable SD card support without correct COMMON_CLK support,
best viewed with 'git diff -w -b', NOT acceptable for mainline (NAKed)

Signed-off-by: Gerhard Sittig 
[ a13xp0p0...@gmail.com: resolve little patch conflict ]
---
 drivers/mmc/host/mxcmmc.c | 42 --
 1 file changed, 28 insertions(+), 14 deletions(-)

diff --git a/drivers/mmc/host/mxcmmc.c b/drivers/mmc/host/mxcmmc.c
index f7199c8..ddefa60 100644
--- a/drivers/mmc/host/mxcmmc.c
+++ b/drivers/mmc/host/mxcmmc.c
@@ -1123,20 +1123,29 @@ static int mxcmci_probe(struct platform_device *pdev)
host->res = r;
host->irq = irq;
 
-   host->clk_ipg = devm_clk_get(&pdev->dev, "ipg");
-   if (IS_ERR(host->clk_ipg)) {
-   ret = PTR_ERR(host->clk_ipg);
-   goto out_iounmap;
-   }
+   if (!is_mpc512x_mmc(host)) {
+   host->clk_ipg = devm_clk_get(&pdev->dev, "ipg");
+   if (IS_ERR(host->clk_ipg)) {
+   ret = PTR_ERR(host->clk_ipg);
+   goto out_iounmap;
+   }
 
-   host->clk_per = devm_clk_get(&pdev->dev, "per");
-   if (IS_ERR(host->clk_per)) {
-   ret = PTR_ERR(host->clk_per);
-   goto out_iounmap;
+   host->clk_per = devm_clk_get(&pdev->dev, "per");
+   if (IS_ERR(host->clk_per)) {
+   ret = PTR_ERR(host->clk_per);
+   goto out_iounmap;
+   }
+   } else {
+   host->clk_per = devm_clk_get(&pdev->dev, "sdhc_clk");
+   if (IS_ERR(host->clk_per)) {
+   ret = PTR_ERR(host->clk_per);
+   goto out_iounmap;
+   }
}
 
clk_prepare_enable(host->clk_per);
-   clk_prepare_enable(host->clk_ipg);
+   if (host->clk_ipg)
+   clk_prepare_enable(host->clk_ipg);
 
mxcmci_softreset(host);
 
@@ -1206,7 +1215,8 @@ out_free_dma:
dma_release_channel(host->dma);
 out_clk_put:
clk_disable_unprepare(host->clk_per);
-   clk_disable_unprepare(host->clk_ipg);
+   if (host->clk_ipg)
+   clk_disable_unprepare(host->clk_ipg);
 out_iounmap:
iounmap(host->base);
 out_free:
@@ -1236,7 +1246,8 @@ static int mxcmci_remove(struct platform_device *pdev)
dma_release_channel(host->dma);
 
clk_disable_unprepare(host->clk_per);
-   clk_disable_unprepare(host->clk_ipg);
+   if (host->clk_ipg)
+   clk_disable_unprepare(host->clk_ipg);
 
release_mem_region(host->res->start, resource_size(host->res));
 
@@ -1252,7 +1263,9 @@ static int mxcmci_suspend(struct device *dev)
struct mxcmci_host *host = mmc_priv(mmc);
 
clk_disable_unprepare(host->clk_per);
-   clk_disable_unprepare(host->clk_ipg);
+   if (host->clk_ipg)
+   clk_disable_unprepare(host->clk_ipg);
+
return 0;
 }
 
@@ -1262,7 +1275,8 @@ static int mxcmci_resume(struct device *dev)
struct mxcmci_host *host = mmc_priv(mmc);
 
clk_prepare_enable(host->clk_per);
-   clk_prepare_enable(host->clk_ipg);
+   if (host->clk_ipg)
+   clk_prepare_enable(host->clk_ipg);
return 0;
 }
 
-- 
1.8.4.2

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[PATCH RFC v7 5/6] dma: mpc512x: register for device tree channel lookup

[Alexander Popov]

From: Gerhard Sittig 

register the controller for device tree based lookup of DMA channels
(non-fatal for backwards compatibility with older device trees) and
provide the '#dma-cells' property in the shared mpc5121.dtsi file

Signed-off-by: Gerhard Sittig 
[ a13xp0p0...@gmail.com: resolve little patch conflict and put
  MPC512x DMA controller bindings document to a separate patch ]
---
 arch/powerpc/boot/dts/mpc5121.dtsi |  1 +
 drivers/dma/mpc512x_dma.c  | 21 ++---
 2 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/boot/dts/mpc5121.dtsi 
b/arch/powerpc/boot/dts/mpc5121.dtsi
index 2c0e155..7f9d14f 100644
--- a/arch/powerpc/boot/dts/mpc5121.dtsi
+++ b/arch/powerpc/boot/dts/mpc5121.dtsi
@@ -498,6 +498,7 @@
compatible = "fsl,mpc5121-dma";
reg = <0x14000 0x1800>;
interrupts = <65 0x8>;
+   #dma-cells = <1>;
};
};
 
diff --git a/drivers/dma/mpc512x_dma.c b/drivers/dma/mpc512x_dma.c
index b978ef1..1e0b8cf 100644
--- a/drivers/dma/mpc512x_dma.c
+++ b/drivers/dma/mpc512x_dma.c
@@ -50,6 +50,7 @@
 #include 
 #include 
 #include 
+#include 
 #include 
 
 #include 
@@ -1013,11 +1014,23 @@ static int mpc_dma_probe(struct platform_device *op)
/* Register DMA engine */
dev_set_drvdata(dev, mdma);
retval = dma_async_device_register(dma);
-   if (retval) {
-   devm_free_irq(dev, mdma->irq, mdma);
-   irq_dispose_mapping(mdma->irq);
+   if (retval)
+   goto out_irq;
+
+   /* register with OF helpers for DMA lookups (nonfatal) */
+   if (dev->of_node) {
+   retval = of_dma_controller_register(dev->of_node,
+   of_dma_xlate_by_chan_id,
+   mdma);
+   if (retval)
+   dev_warn(dev, "could not register for OF lookup\n");
}
 
+   return 0;
+
+out_irq:
+   devm_free_irq(dev, mdma->irq, mdma);
+   irq_dispose_mapping(mdma->irq);
return retval;
 }
 
@@ -1026,6 +1039,8 @@ static int mpc_dma_remove(struct platform_device *op)
struct device *dev = &op->dev;
struct mpc_dma *mdma = dev_get_drvdata(dev);
 
+   if (dev->of_node)
+   of_dma_controller_free(dev->of_node);
dma_async_device_unregister(&mdma->dma);
devm_free_irq(dev, mdma->irq, mdma);
irq_dispose_mapping(mdma->irq);
-- 
1.8.4.2

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[PATCH RFC v7 0/6] MPC512x DMA slave s/g support, OF DMA lookup

[Alexander Popov]

v2013/7/14 Gerhard Sittig :
> this series
> - introduces slave s/g support (that's support for DMA transfers which
>involve peripherals in contrast to mem-to-mem transfers)
> - adds device tree based lookup support for DMA channels
> - combines floating patches and related feedback which already covered
>several aspects of what the suggested LPB driver needs, to demonstrate
>how integration might be done
> - carries Q&D SD card support to enable another DMA client during test,
>while this patch needs to get dropped upon pickup

Changes in v2:
> - re-order mpc8308 related code paths for improved readability, no
>change in behaviour, introduction of symbolic channel names here
>already
> - squash 'execute() start condition' and 'terminate all' into the
>introduction of 'slave s/g prep' and 'device control' support; refuse
>s/g lists with more than one item since slave support is operational
>yet proper s/g support is missing (can get addressed later)
> - always start transfers from software on MPC8308 as there are no
>external request lines for peripheral flow control
> - drop dt-bindings header file and symbolic channel names in OF nodes

Changes in v3 and v4:
 Part 1/5:
 - use #define instead of enum since individual channels don't require
special handling.
 Part 2/5:
 - add a flag "will_access_peripheral" to DMA transfer descriptor
according recommendations of Gerhard Sittig.
This flag is set in mpc_dma_prep_memcpy() and mpc_dma_prep_slave_sg()
and is evaluated in mpc_dma_execute() to choose a type of start for
the transfer.
 - prevent descriptors of transfers which involve peripherals from
being chained together;
each of such transfers needs hardware initiated start.
 - add locking while working with struct mpc_dma_chan
according recommendations of Lars-Peter Clausen.
 - remove default nbytes value. Client kernel modules must set
src_maxburst and dst_maxburst fields of struct dma_slave_config 
(dmaengine.h).

Changes in v5:
 Part 2/5:
 - add and improve comments;
 - improve the code moving transfer descriptors from 'queued' to 'active' list
in mpc_dma_execute();
 - allow mpc_dma_prep_slave_sg() to run with non-empty 'active' list;
 - take 'mdesc' back to 'free' list in case of error in mpc_dma_prep_slave_sg();
 - improve checks of the transfer parameters;
 - provide the default value for 'maxburst' in mpc_dma_device_control().

Changes in v6:
 Part 2/5:
 - remove doubtful comment;
 - fix coding style issues;
 - set default value for 'maxburst' to 1 which applies to most cases;
 Part 3/5:
 - use dma_get_slave_channel() instead of dma_request_channel()
in new function of_dma_xlate_by_chan_id() according recommendations of
Arnd Bergmann;
 Part 4/5:
 - set DMA_PRIVATE flag for MPC512x DMA controller since its driver relies on
of_dma_xlate_by_chan_id() which doesn't use dma_request_channel()
any more; (removed in v7)
 - resolve little patch conflict;
 Part 5/5:
 - resolve little patch conflict;

Changes in v7:
 Part 2:
 - improve comment;
 Part 4:
 - split in two separate patches. Part 4/6 contains device tree
binding document and in part 5/6 MPC512x DMA controller is registered
for device tree channel lookup;
 - remove setting DMA_PRIVATE flag for MPC512x DMA controller from part 5/6;

> known issues:
> - it's yet to get confirmed whether MPC8308 can use slave support or
>whether the DMA controller's driver shall actively reject it, the
>information that's available so far suggests that peripheral transfers
>to IP bus attached I/O is useful and shall not get blocked right away
 - adding support for transfers which don't increment the RAM address or
do increment the peripheral "port's" address is easy with
this implementation; but which options of the common API
should be used for specifying such transfers?
 - device tree binding document for the MPC512x DMA controller needs
to be improved.


Alexander Popov (3):
  dma: mpc512x: reorder mpc8308 specific instructions
  dma: mpc512x: add support for peripheral transfers
  dma: of: Add common xlate function for matching by channel id

Gerhard Sittig (3):
  dma: mpc512x: add device tree binding document
  dma: mpc512x: register for device tree channel lookup
  HACK mmc: mxcmmc: enable clocks for the MPC512x

 .../devicetree/bindings/dma/mpc512x-dma.txt|  55 
 arch/powerpc/boot/dts/mpc5121.dtsi |   1 +
 drivers/dma/mpc512x_dma.c  | 293 +++--
 drivers/dma/of-dma.c   |  35 +++
 drivers/mmc/host/mxcmmc.c  |  42 ++-
 include/linux/of_dma.h |   4 +
 6

Re: [PATCH RFC v6 4/5] dma: mpc512x: register for device tree channel lookup

[Alexander Popov]

Hello Gerhard.
Thanks for your review.

2013/12/26 Gerhard Sittig :
> [ dropping devicetree, we're DMA specific here ]
>
> On Tue, Dec 24, 2013 at 16:06 +0400, Alexander Popov wrote:
>>
>> --- a/drivers/dma/mpc512x_dma.c
>> +++ b/drivers/dma/mpc512x_dma.c
>> [ ... ]
>> @@ -950,6 +951,7 @@ static int mpc_dma_probe(struct platform_device *op)
>>   INIT_LIST_HEAD(&dma->channels);
>>   dma_cap_set(DMA_MEMCPY, dma->cap_mask);
>>   dma_cap_set(DMA_SLAVE, dma->cap_mask);
>> + dma_cap_set(DMA_PRIVATE, dma->cap_mask);
>>
>>   for (i = 0; i < dma->chancnt; i++) {
>>   mchan = &mdma->channels[i];
>
> What are the implications of this?  Is a comment due?

I've involved DMA_PRIVATE flag because new of_dma_xlate_by_chan_id()
uses dma_get_slave_channel() instead of dma_request_channel()
(PATCH RFC v6 3/5). This flag is implicitly set in dma_request_channel(),
but is not set in dma_get_slave_channel().

There are only two places in the mainline kernel, where
dma_get_slave_channel() is used. I've picked up the idea
at one of these places. Please look at this patch:
http://www.spinics.net/lists/arm-kernel/msg268718.html

> I haven't found documentation about the DMA_PRIVATE flag, only
> saw commit 59b5ec21446b9 "dmaengine: introduce
> dma_request_channel and private channels".

Unfortunately I didn't find any description of DMA_PRIVATE flag too.
But the comment at the beginning of drivers/dma/dmaengine.c
may give a clue. Quotation:
  * subsystem can get access to a channel by calling dmaengine_get() followed
  * by dma_find_channel(), or if it has need for an exclusive channel
it can call
  * dma_request_channel().  Once a channel is allocated a reference is taken
  * against its corresponding driver to disable removal.

DMA_PRIVATE capability flag might indicate that the DMA controller
can provide exclusive channels to its clients. Please correct me if I'm wrong.

> Alex, unless I'm
> missing something this one-line change is quite a change in
> semantics, and has dramatic influence on the code's behaviour
> (ignores the DMA controller when looking for channels that can do
> mem-to-mem transfers)

Excuse me, Gerhard, I don't see what you mean.
Could you point to the corresponding code?

> Consider the fact that this driver
> handles both MPC5121 as well as MPC8308 hardware.

Ah, yes, sorry. I should certainly fix this, if setting of DMA_PRIVATE flag
is needed at all.

Thanks!

Best regards,
Alexander
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[PATCH RFC v6 4/5] dma: mpc512x: register for device tree channel lookup

[Alexander Popov]

From: Gerhard Sittig 

register the controller for device tree based lookup of DMA channels
(non-fatal for backwards compatibility with older device trees), provide
the '#dma-cells' property in the shared mpc5121.dtsi file, and introduce
a bindings document for the MPC512x DMA controller

Signed-off-by: Gerhard Sittig 
[ a13xp0p0...@gmail.com: resolve little patch conflict ]
[ a13xp0p0...@gmail.com: set DMA_PRIVATE flag for MPC512x DMA controller ]
Signed-off-by: Alexander Popov 
---
 .../devicetree/bindings/dma/mpc512x-dma.txt| 55 ++
 arch/powerpc/boot/dts/mpc5121.dtsi |  1 +
 drivers/dma/mpc512x_dma.c  | 22 +++--
 3 files changed, 75 insertions(+), 3 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/dma/mpc512x-dma.txt

diff --git a/Documentation/devicetree/bindings/dma/mpc512x-dma.txt 
b/Documentation/devicetree/bindings/dma/mpc512x-dma.txt
new file mode 100644
index 000..a4867d5
--- /dev/null
+++ b/Documentation/devicetree/bindings/dma/mpc512x-dma.txt
@@ -0,0 +1,55 @@
+* Freescale MPC512x DMA Controller
+
+The DMA controller in the Freescale MPC512x SoC can move blocks of
+memory contents between memory and peripherals or memory to memory.
+
+Refer to the "Generic DMA Controller and DMA request bindings" description
+in the dma.txt file for a more detailled discussion of the binding.  The
+MPC512x DMA engine binding follows the common scheme, but doesn't provide
+support for the optional channels and requests counters (those values are
+derived from the detected hardware features) and has a fixed client
+specifier length of 1 integer cell (the value is the DMA channel, since
+the DMA controller uses a fixed assignment of request lines per channel).
+
+
+DMA controller node properties:
+
+Required properties:
+- compatible:  should be "fsl,mpc5121-dma"
+- reg: address and size of the DMA controller's register set
+- interrupts:  interrupt spec for the DMA controller
+
+Optional properties:
+- #dma-cells:  must be <1>, describes the number of integer cells
+   needed to specify the 'dmas' property in client nodes,
+   strongly recommended since common client helper code
+   uses this property
+
+Example:
+
+   dma0: dma@14000 {
+   compatible = "fsl,mpc5121-dma";
+   reg = <0x14000 0x1800>;
+   interrupts = <65 0x8>;
+   #dma-cells = <1>;
+   };
+
+
+Client node properties:
+
+Required properties:
+- dmas:list of DMA specifiers, consisting each of a 
handle
+   for the DMA controller and integer cells to specify
+   the channel used within the DMA controller
+- dma-names:   list of identifier strings for the DMA specifiers,
+   client device driver code uses these strings to
+   have DMA channels looked up at the controller
+
+Example:
+
+   sdhc@1500 {
+   compatible = "fsl,mpc5121-sdhc";
+   /* ... */
+   dmas = <&dma0 30>;
+   dma-names = "rx-tx";
+   };
diff --git a/arch/powerpc/boot/dts/mpc5121.dtsi 
b/arch/powerpc/boot/dts/mpc5121.dtsi
index 2d7cb04..15b7860 100644
--- a/arch/powerpc/boot/dts/mpc5121.dtsi
+++ b/arch/powerpc/boot/dts/mpc5121.dtsi
@@ -389,6 +389,7 @@
compatible = "fsl,mpc5121-dma";
reg = <0x14000 0x1800>;
interrupts = <65 0x8>;
+   #dma-cells = <1>;
};
};
 
diff --git a/drivers/dma/mpc512x_dma.c b/drivers/dma/mpc512x_dma.c
index a7e7749..8fabb52 100644
--- a/drivers/dma/mpc512x_dma.c
+++ b/drivers/dma/mpc512x_dma.c
@@ -50,6 +50,7 @@
 #include 
 #include 
 #include 
+#include 
 #include 
 
 #include 
@@ -950,6 +951,7 @@ static int mpc_dma_probe(struct platform_device *op)
INIT_LIST_HEAD(&dma->channels);
dma_cap_set(DMA_MEMCPY, dma->cap_mask);
dma_cap_set(DMA_SLAVE, dma->cap_mask);
+   dma_cap_set(DMA_PRIVATE, dma->cap_mask);
 
for (i = 0; i < dma->chancnt; i++) {
mchan = &mdma->channels[i];
@@ -1013,11 +1015,23 @@ static int mpc_dma_probe(struct platform_device *op)
/* Register DMA engine */
dev_set_drvdata(dev, mdma);
retval = dma_async_device_register(dma);
-   if (retval) {
-   devm_free_irq(dev, mdma->irq, mdma);
-   irq_dispose_mapping(mdma->irq);
+   if (retval)
+   goto out_irq;
+
+   /* register with OF helpers for DMA lookups (nonfatal) */
+   if (dev->of_node) {
+   retval = of_dma_controller_register(dev->of_node,
+

[PATCH RFC v6 5/5] HACK mmc: mxcmmc: enable clocks for the MPC512x

[Alexander Popov]

From: Gerhard Sittig 

Q&D HACK to enable SD card support without correct COMMON_CLK support,
best viewed with 'git diff -w -b', NOT acceptable for mainline (NAKed)

Signed-off-by: Gerhard Sittig 
[ a13xp0p0...@gmail.com: resolve little patch conflict ]
Signed-off-by: Alexander Popov 
---
 drivers/mmc/host/mxcmmc.c | 42 --
 1 file changed, 28 insertions(+), 14 deletions(-)

diff --git a/drivers/mmc/host/mxcmmc.c b/drivers/mmc/host/mxcmmc.c
index f7199c8..ddefa60 100644
--- a/drivers/mmc/host/mxcmmc.c
+++ b/drivers/mmc/host/mxcmmc.c
@@ -1123,20 +1123,29 @@ static int mxcmci_probe(struct platform_device *pdev)
host->res = r;
host->irq = irq;
 
-   host->clk_ipg = devm_clk_get(&pdev->dev, "ipg");
-   if (IS_ERR(host->clk_ipg)) {
-   ret = PTR_ERR(host->clk_ipg);
-   goto out_iounmap;
-   }
+   if (!is_mpc512x_mmc(host)) {
+   host->clk_ipg = devm_clk_get(&pdev->dev, "ipg");
+   if (IS_ERR(host->clk_ipg)) {
+   ret = PTR_ERR(host->clk_ipg);
+   goto out_iounmap;
+   }
 
-   host->clk_per = devm_clk_get(&pdev->dev, "per");
-   if (IS_ERR(host->clk_per)) {
-   ret = PTR_ERR(host->clk_per);
-   goto out_iounmap;
+   host->clk_per = devm_clk_get(&pdev->dev, "per");
+   if (IS_ERR(host->clk_per)) {
+   ret = PTR_ERR(host->clk_per);
+   goto out_iounmap;
+   }
+   } else {
+   host->clk_per = devm_clk_get(&pdev->dev, "sdhc_clk");
+   if (IS_ERR(host->clk_per)) {
+   ret = PTR_ERR(host->clk_per);
+   goto out_iounmap;
+   }
}
 
clk_prepare_enable(host->clk_per);
-   clk_prepare_enable(host->clk_ipg);
+   if (host->clk_ipg)
+   clk_prepare_enable(host->clk_ipg);
 
mxcmci_softreset(host);
 
@@ -1206,7 +1215,8 @@ out_free_dma:
dma_release_channel(host->dma);
 out_clk_put:
clk_disable_unprepare(host->clk_per);
-   clk_disable_unprepare(host->clk_ipg);
+   if (host->clk_ipg)
+   clk_disable_unprepare(host->clk_ipg);
 out_iounmap:
iounmap(host->base);
 out_free:
@@ -1236,7 +1246,8 @@ static int mxcmci_remove(struct platform_device *pdev)
dma_release_channel(host->dma);
 
clk_disable_unprepare(host->clk_per);
-   clk_disable_unprepare(host->clk_ipg);
+   if (host->clk_ipg)
+   clk_disable_unprepare(host->clk_ipg);
 
release_mem_region(host->res->start, resource_size(host->res));
 
@@ -1252,7 +1263,9 @@ static int mxcmci_suspend(struct device *dev)
struct mxcmci_host *host = mmc_priv(mmc);
 
clk_disable_unprepare(host->clk_per);
-   clk_disable_unprepare(host->clk_ipg);
+   if (host->clk_ipg)
+   clk_disable_unprepare(host->clk_ipg);
+
return 0;
 }
 
@@ -1262,7 +1275,8 @@ static int mxcmci_resume(struct device *dev)
struct mxcmci_host *host = mmc_priv(mmc);
 
clk_prepare_enable(host->clk_per);
-   clk_prepare_enable(host->clk_ipg);
+   if (host->clk_ipg)
+   clk_prepare_enable(host->clk_ipg);
return 0;
 }
 
-- 
1.8.4.2

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[PATCH RFC v6 3/5] dma: of: Add common xlate function for matching by channel id

[Alexander Popov]

This patch adds a new common OF dma xlate callback function which will match a
channel by it's id. The binding expects one integer argument which it will use 
to
lookup the channel by the id.

Unlike of_dma_simple_xlate this function is able to handle a system with
multiple DMA controllers. When registering the of dma provider with
of_dma_controller_register a pointer to the dma_device struct which is
associated with the dt node needs to passed as the data parameter.
New function will use this pointer to match only channels which belong to the
specified DMA controller.

Signed-off-by: Alexander Popov 
---
 drivers/dma/of-dma.c   | 35 +++
 include/linux/of_dma.h |  4 
 2 files changed, 39 insertions(+)

diff --git a/drivers/dma/of-dma.c b/drivers/dma/of-dma.c
index 0b88dd3..03a375e 100644
--- a/drivers/dma/of-dma.c
+++ b/drivers/dma/of-dma.c
@@ -215,3 +215,38 @@ struct dma_chan *of_dma_simple_xlate(struct 
of_phandle_args *dma_spec,
&dma_spec->args[0]);
 }
 EXPORT_SYMBOL_GPL(of_dma_simple_xlate);
+
+/**
+ * of_dma_xlate_by_chan_id - Translate dt property to DMA channel by channel id
+ * @dma_spec:  pointer to DMA specifier as found in the device tree
+ * @of_dma:pointer to DMA controller data
+ *
+ * This function can be used as the of xlate callback for DMA driver which 
wants
+ * to match the channel based on the channel id. When using this xlate function
+ * the #dma-cells propety of the DMA controller dt node needs to be set to 1.
+ * The data parameter of of_dma_controller_register must be a pointer to the
+ * dma_device struct the function should match upon.
+ *
+ * Returns pointer to appropriate dma channel on success or NULL on error.
+ */
+struct dma_chan *of_dma_xlate_by_chan_id(struct of_phandle_args *dma_spec,
+struct of_dma *ofdma)
+{
+   struct dma_device *dev = ofdma->of_dma_data;
+   struct dma_chan *chan, *candidate = NULL;
+
+   if (!dev || dma_spec->args_count != 1)
+   return NULL;
+
+   list_for_each_entry(chan, &dev->channels, device_node)
+   if (chan->chan_id == dma_spec->args[0]) {
+   candidate = chan;
+   break;
+   }
+
+   if (!candidate)
+   return NULL;
+
+   return dma_get_slave_channel(candidate);
+}
+EXPORT_SYMBOL_GPL(of_dma_xlate_by_chan_id);
diff --git a/include/linux/of_dma.h b/include/linux/of_dma.h
index ae36298..56bc026 100644
--- a/include/linux/of_dma.h
+++ b/include/linux/of_dma.h
@@ -41,6 +41,8 @@ extern struct dma_chan *of_dma_request_slave_channel(struct 
device_node *np,
 const char *name);
 extern struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_spec,
struct of_dma *ofdma);
+extern struct dma_chan *of_dma_xlate_by_chan_id(struct of_phandle_args 
*dma_spec,
+   struct of_dma *ofdma);
 #else
 static inline int of_dma_controller_register(struct device_node *np,
struct dma_chan *(*of_dma_xlate)
@@ -66,6 +68,8 @@ static inline struct dma_chan *of_dma_simple_xlate(struct 
of_phandle_args *dma_s
return NULL;
 }
 
+#define of_dma_xlate_by_chan_id NULL
+
 #endif
 
 #endif /* __LINUX_OF_DMA_H */
-- 
1.8.4.2

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[PATCH RFC v6 2/5] dma: mpc512x: add support for peripheral transfers

[Alexander Popov]

Introduce support for slave s/g transfer preparation and the associated
device control callback in the MPC512x DMA controller driver, which adds
support for data transfers between memory and peripheral I/O to the
previously supported mem-to-mem transfers.

Signed-off-by: Alexander Popov 
---
 drivers/dma/mpc512x_dma.c | 230 +-
 1 file changed, 225 insertions(+), 5 deletions(-)

diff --git a/drivers/dma/mpc512x_dma.c b/drivers/dma/mpc512x_dma.c
index 2ce248b..a7e7749 100644
--- a/drivers/dma/mpc512x_dma.c
+++ b/drivers/dma/mpc512x_dma.c
@@ -2,6 +2,7 @@
  * Copyright (C) Freescale Semicondutor, Inc. 2007, 2008.
  * Copyright (C) Semihalf 2009
  * Copyright (C) Ilya Yanok, Emcraft Systems 2010
+ * Copyright (C) Alexander Popov, Promcontroller 2013
  *
  * Written by Piotr Ziecik . Hardware description
  * (defines, structures and comments) was taken from MPC5121 DMA driver
@@ -29,8 +30,15 @@
  */
 
 /*
- * This is initial version of MPC5121 DMA driver. Only memory to memory
- * transfers are supported (tested using dmatest module).
+ * This version of MPC5121 DMA driver supports
+ * memory to memory data transfers (tested using dmatest module) and
+ * data transfers between memory and peripheral I/O memory
+ * by means of slave s/g with these limitations:
+ * - chunked transfers (transfers with more than one part) are refused
+ * as long as proper support for scatter/gather is missing;
+ * - transfers on MPC8308 always start from software as this SoC appears
+ * not to have external request lines for peripheral flow control;
+ * - minimal memory <-> I/O memory transfer size is 4 bytes.
  */
 
 #include 
@@ -189,6 +197,7 @@ struct mpc_dma_desc {
dma_addr_t  tcd_paddr;
int error;
struct list_headnode;
+   int will_access_peripheral;
 };
 
 struct mpc_dma_chan {
@@ -201,6 +210,10 @@ struct mpc_dma_chan {
struct mpc_dma_tcd  *tcd;
dma_addr_t  tcd_paddr;
 
+   /* Settings for access to peripheral FIFO */
+   dma_addr_t  per_paddr;  /* FIFO address */
+   u32 tcd_nunits;
+
/* Lock for this structure */
spinlock_t  lock;
 };
@@ -251,8 +264,21 @@ static void mpc_dma_execute(struct mpc_dma_chan *mchan)
struct mpc_dma_desc *mdesc;
int cid = mchan->chan.chan_id;
 
-   /* Move all queued descriptors to active list */
-   list_splice_tail_init(&mchan->queued, &mchan->active);
+   while (!list_empty(&mchan->queued)) {
+   mdesc = list_first_entry(&mchan->queued,
+   struct mpc_dma_desc, node);
+
+   /* Grab either several mem-to-mem transfer descriptors
+* or one peripheral transfer descriptor,
+* don't mix mem-to-mem and peripheral transfer descriptors
+* within the same 'active' list. */
+   if (mdesc->will_access_peripheral) {
+   if (list_empty(&mchan->active))
+   list_move_tail(&mdesc->node, &mchan->active);
+   break;
+   } else
+   list_move_tail(&mdesc->node, &mchan->active);
+   }
 
/* Chain descriptors into one transaction */
list_for_each_entry(mdesc, &mchan->active, node) {
@@ -278,7 +304,17 @@ static void mpc_dma_execute(struct mpc_dma_chan *mchan)
 
if (first != prev)
mdma->tcd[cid].e_sg = 1;
-   out_8(&mdma->regs->dmassrt, cid);
+
+   if (mdma->is_mpc8308) {
+   /* MPC8308, no request lines, software initiated start */
+   out_8(&mdma->regs->dmassrt, cid);
+   } else if (first->will_access_peripheral) {
+   /* peripherals involved, start by external request signal */
+   out_8(&mdma->regs->dmaserq, cid);
+   } else {
+   /* memory to memory transfer, software initiated start */
+   out_8(&mdma->regs->dmassrt, cid);
+   }
 }
 
 /* Handle interrupt on one half of DMA controller (32 channels) */
@@ -596,6 +632,7 @@ mpc_dma_prep_memcpy(struct dma_chan *chan, dma_addr_t dst, 
dma_addr_t src,
}
 
mdesc->error = 0;
+   mdesc->will_access_peripheral = 0;
tcd = mdesc->tcd;
 
/* Prepare Transfer Control Descriptor for this transaction */
@@ -643,6 +680,186 @@ mpc_dma_prep_memcpy(struct dma_chan *chan, dma_addr_t 
dst, dma_addr_t src,
return &mdesc->desc;
 }
 
+static struct dma_async_tx_descriptor *
+mpc_dma_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
+   unsigned int sg_len, enum dma_transfer

[PATCH RFC v6 0/5] MPC512x DMA slave s/g support, OF DMA lookup

[Alexander Popov]

v2013/7/14 Gerhard Sittig :
> this series
> - introduces slave s/g support (that's support for DMA transfers which
>involve peripherals in contrast to mem-to-mem transfers)
> - adds device tree based lookup support for DMA channels
> - combines floating patches and related feedback which already covered
>several aspects of what the suggested LPB driver needs, to demonstrate
>how integration might be done
> - carries Q&D SD card support to enable another DMA client during test,
>while this patch needs to get dropped upon pickup

Changes in v2:
> - re-order mpc8308 related code paths for improved readability, no
>change in behaviour, introduction of symbolic channel names here
>already
> - squash 'execute() start condition' and 'terminate all' into the
>introduction of 'slave s/g prep' and 'device control' support; refuse
>s/g lists with more than one item since slave support is operational
>yet proper s/g support is missing (can get addressed later)
> - always start transfers from software on MPC8308 as there are no
>external request lines for peripheral flow control
> - drop dt-bindings header file and symbolic channel names in OF nodes

Changes in v3 and v4:
 Part 1/5:
 - use #define instead of enum since individual channels don't require
special handling.
 Part 2/5:
 - add a flag "will_access_peripheral" to DMA transfer descriptor
according recommendations of Gerhard Sittig.
This flag is set in mpc_dma_prep_memcpy() and mpc_dma_prep_slave_sg()
and is evaluated in mpc_dma_execute() to choose a type of start for
the transfer.
 - prevent descriptors of transfers which involve peripherals from
being chained together;
each of such transfers needs hardware initiated start.
 - add locking while working with struct mpc_dma_chan
according recommendations of Lars-Peter Clausen.
 - remove default nbytes value. Client kernel modules must set
src_maxburst and dst_maxburst fields of struct dma_slave_config 
(dmaengine.h).

Changes in v5:
 Part 2/5:
 - add and improve comments;
 - improve the code moving transfer descriptors from 'queued' to 'active' list
in mpc_dma_execute();
 - allow mpc_dma_prep_slave_sg() to run with non-empty 'active' list;
 - take 'mdesc' back to 'free' list in case of error in mpc_dma_prep_slave_sg();
 - improve checks of the transfer parameters;
 - provide the default value for 'maxburst' in mpc_dma_device_control().

Changes in v6:
 Part 2/5:
 - remove doubtful comment;
 - fix coding style issues;
 - set default value for 'maxburst' to 1 which applies to most cases;
 Part 3/5:
 - use dma_get_slave_channel() instead of dma_request_channel()
in new function of_dma_xlate_by_chan_id() according recommendations of
Arnd Bergmann;
 Part 4/5:
 - set DMA_PRIVATE flag for MPC512x DMA controller since its driver relies on
of_dma_xlate_by_chan_id() which doesn't use dma_request_channel()
any more;
 - resolve little patch conflict;
 Part 5/5:
 - resolve little patch conflict;

> known issues:
> - it's yet to get confirmed whether MPC8308 can use slave support or
>whether the DMA controller's driver shall actively reject it, the
>information that's available so far suggests that peripheral transfers
>to IP bus attached I/O is useful and shall not get blocked right away
 - adding support for transfers which don't increment the RAM address or
do increment the peripheral "port's" address is easy with
this implementation; but which options of the common API
should be used for specifying such transfers?


Alexander Popov (3):
  dma: mpc512x: reorder mpc8308 specific instructions
  dma: mpc512x: add support for peripheral transfers
  dma: of: Add common xlate function for matching by channel id

Gerhard Sittig (2):
  dma: mpc512x: register for device tree channel lookup
  HACK mmc: mxcmmc: enable clocks for the MPC512x

 .../devicetree/bindings/dma/mpc512x-dma.txt|  55 
 arch/powerpc/boot/dts/mpc5121.dtsi |   1 +
 drivers/dma/mpc512x_dma.c  | 294 +++--
 drivers/dma/of-dma.c   |  35 +++
 drivers/mmc/host/mxcmmc.c  |  42 ++-
 include/linux/of_dma.h |   4 +
 6 files changed, 392 insertions(+), 39 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/dma/mpc512x-dma.txt

-- 
1.8.4.2

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[PATCH RFC v6 1/5] dma: mpc512x: reorder mpc8308 specific instructions

[Alexander Popov]

Concentrate the specific code for MPC8308 in the 'if' branch
and handle MPC512x in the 'else' branch.
This modification only reorders instructions but doesn't change behaviour.

Signed-off-by: Alexander Popov 
---
 drivers/dma/mpc512x_dma.c | 42 +-
 1 file changed, 25 insertions(+), 17 deletions(-)

diff --git a/drivers/dma/mpc512x_dma.c b/drivers/dma/mpc512x_dma.c
index 448750d..2ce248b 100644
--- a/drivers/dma/mpc512x_dma.c
+++ b/drivers/dma/mpc512x_dma.c
@@ -52,9 +52,17 @@
 #define MPC_DMA_DESCRIPTORS64
 
 /* Macro definitions */
-#define MPC_DMA_CHANNELS   64
 #define MPC_DMA_TCD_OFFSET 0x1000
 
+/*
+ * Maximum channel counts for individual hardware variants
+ * and the maximum channel count over all supported controllers,
+ * used for data structure size
+ */
+#define MPC8308_DMACHAN_MAX16
+#define MPC512x_DMACHAN_MAX64
+#define MPC_DMA_CHANNELS   64
+
 /* Arbitration mode of group and channel */
 #define MPC_DMA_DMACR_EDCG (1 << 31)
 #define MPC_DMA_DMACR_ERGA (1 << 3)
@@ -710,10 +718,10 @@ static int mpc_dma_probe(struct platform_device *op)
 
dma = &mdma->dma;
dma->dev = dev;
-   if (!mdma->is_mpc8308)
-   dma->chancnt = MPC_DMA_CHANNELS;
+   if (mdma->is_mpc8308)
+   dma->chancnt = MPC8308_DMACHAN_MAX;
else
-   dma->chancnt = 16; /* MPC8308 DMA has only 16 channels */
+   dma->chancnt = MPC512x_DMACHAN_MAX;
dma->device_alloc_chan_resources = mpc_dma_alloc_chan_resources;
dma->device_free_chan_resources = mpc_dma_free_chan_resources;
dma->device_issue_pending = mpc_dma_issue_pending;
@@ -747,7 +755,19 @@ static int mpc_dma_probe(struct platform_device *op)
 * - Round-robin group arbitration,
 * - Round-robin channel arbitration.
 */
-   if (!mdma->is_mpc8308) {
+   if (mdma->is_mpc8308) {
+   /* MPC8308 has 16 channels and lacks some registers */
+   out_be32(&mdma->regs->dmacr, MPC_DMA_DMACR_ERCA);
+
+   /* enable snooping */
+   out_be32(&mdma->regs->dmagpor, MPC_DMA_DMAGPOR_SNOOP_ENABLE);
+   /* Disable error interrupts */
+   out_be32(&mdma->regs->dmaeeil, 0);
+
+   /* Clear interrupts status */
+   out_be32(&mdma->regs->dmaintl, 0x);
+   out_be32(&mdma->regs->dmaerrl, 0x);
+   } else {
out_be32(&mdma->regs->dmacr, MPC_DMA_DMACR_EDCG |
MPC_DMA_DMACR_ERGA | 
MPC_DMA_DMACR_ERCA);
 
@@ -768,18 +788,6 @@ static int mpc_dma_probe(struct platform_device *op)
/* Route interrupts to IPIC */
out_be32(&mdma->regs->dmaihsa, 0);
out_be32(&mdma->regs->dmailsa, 0);
-   } else {
-   /* MPC8308 has 16 channels and lacks some registers */
-   out_be32(&mdma->regs->dmacr, MPC_DMA_DMACR_ERCA);
-
-   /* enable snooping */
-   out_be32(&mdma->regs->dmagpor, MPC_DMA_DMAGPOR_SNOOP_ENABLE);
-   /* Disable error interrupts */
-   out_be32(&mdma->regs->dmaeeil, 0);
-
-   /* Clear interrupts status */
-   out_be32(&mdma->regs->dmaintl, 0x);
-   out_be32(&mdma->regs->dmaerrl, 0x);
}
 
/* Register DMA engine */
-- 
1.8.4.2

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Re: [PATCH RFC v5 2/5] dma: mpc512x: add support for peripheral transfers

[Alexander Popov]

2013/11/15 Gerhard Sittig :
> As for the not yet addressed feedback:  From the top of my head I
> can think of the execute comment which contradicts the code
> (which suggests that at least one of them is wrong), and the data
> type mismatch in the config routine (where code just happens to
> work by coincidence).  And in bypassing I noticed that your
> recent submission has coding style issues (braces, indentation),
> which should no longer happen after several iterations as you
> should know how to prepare and check the next version.
I'll doublecheck this and return with improved code.

> Without feedback, reviewers
> may see several submissions which suffer from the same issues,
> and expect more to show up and thus feel that their feedback is
> getting ignored.  Which quickly becomes tiring.
Thanks for your patience and comprehensive replies.

Best regards,
Alexander.
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Re: [PATCH RFC v5 2/5] dma: mpc512x: add support for peripheral transfers

[Alexander Popov]

Hello, Gerhard!

2013/11/12 Gerhard Sittig :
> Alexander, there is outstanding review feedback for a previous
> version of the series that you haven't addressed yet.  Can you
> please either look into those issues, or state that it's OK to
> leave them and why this is so?
Excuse me for misunderstanding, Gerhard.
I have thoroughly worked on your feedback to RFCv4
and agreed to your points. So I've just wrote RFCv5.
And all the improvements and known issues based on your feedback
are listed in the cover letter [PATCH RFC v5 0/5].

> It would be nice to get a
> response to the feedback that you are given.  It may be
> appropriate not to obey to the feedback, but at least it should
> get considered.
Yes, I see. My implicit response by RFCv5 was not efficient, sorry.
Now should I write a detailed answer in the thread with your feedback
for improving readability of the discussion?

> Have you noticed the recent introduction of the dmaengine@vger
> ML?
No, I didn't.

>Make sure to include it upon the next submission.
Ok, I will.

Thanks.

Best regards,
Alexander.
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Re: [PATCH RFC v5 3/5] dma: of: Add common xlate function for matching by channel id

[Alexander Popov]

2013/11/1 Arnd Bergmann :
> On Friday 01 November 2013, Alexander Popov wrote:
>> + * of_dma_xlate_by_chan_id - Translate dt property to DMA channel by 
>> channel id
>> + * @dma_spec:pointer to DMA specifier as found in the device tree
>> + * @of_dma:  pointer to DMA controller data
>
> This seems rather clumsy, now that we have added the dma_get_slave_channel 
> interface.
> Can you try using that instead of dma_request_channel() now?
>

Thanks, Arnd.
I'll return with the fixed version.

Best regards,
Alexander.
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[PATCH RFC v5 2/5] dma: mpc512x: add support for peripheral transfers

[Alexander Popov]

Introduce support for slave s/g transfer preparation and the associated
device control callback in the MPC512x DMA controller driver, which adds
support for data transfers between memory and peripheral I/O to the
previously supported mem-to-mem transfers.

Signed-off-by: Alexander Popov 
---
 drivers/dma/mpc512x_dma.c | 232 +-
 1 file changed, 227 insertions(+), 5 deletions(-)

diff --git a/drivers/dma/mpc512x_dma.c b/drivers/dma/mpc512x_dma.c
index f41639f..d2ec42d 100644
--- a/drivers/dma/mpc512x_dma.c
+++ b/drivers/dma/mpc512x_dma.c
@@ -2,6 +2,7 @@
  * Copyright (C) Freescale Semicondutor, Inc. 2007, 2008.
  * Copyright (C) Semihalf 2009
  * Copyright (C) Ilya Yanok, Emcraft Systems 2010
+ * Copyright (C) Alexander Popov, Promcontroller 2013
  *
  * Written by Piotr Ziecik . Hardware description
  * (defines, structures and comments) was taken from MPC5121 DMA driver
@@ -29,8 +30,15 @@
  */
 
 /*
- * This is initial version of MPC5121 DMA driver. Only memory to memory
- * transfers are supported (tested using dmatest module).
+ * This version of MPC5121 DMA driver supports
+ * memory to memory data transfers (tested using dmatest module) and
+ * data transfers between memory and peripheral I/O memory
+ * by means of slave s/g with these limitations:
+ * - chunked transfers (transfers with more than one part) are refused
+ * as long as proper support for scatter/gather is missing;
+ * - transfers on MPC8308 always start from software as this SoC appears
+ * not to have external request lines for peripheral flow control;
+ * - minimal memory <-> I/O memory transfer size is 4 bytes.
  */
 
 #include 
@@ -187,6 +195,7 @@ struct mpc_dma_desc {
dma_addr_t  tcd_paddr;
int error;
struct list_headnode;
+   int will_access_peripheral;
 };
 
 struct mpc_dma_chan {
@@ -199,6 +208,10 @@ struct mpc_dma_chan {
struct mpc_dma_tcd  *tcd;
dma_addr_t  tcd_paddr;
 
+   /* Settings for access to peripheral FIFO */
+   dma_addr_t  per_paddr;  /* FIFO address */
+   u32 tcd_nunits;
+
/* Lock for this structure */
spinlock_t  lock;
 };
@@ -249,8 +262,21 @@ static void mpc_dma_execute(struct mpc_dma_chan *mchan)
struct mpc_dma_desc *mdesc;
int cid = mchan->chan.chan_id;
 
-   /* Move all queued descriptors to active list */
-   list_splice_tail_init(&mchan->queued, &mchan->active);
+   while (!list_empty(&mchan->queued)) {
+   mdesc = list_first_entry(&mchan->queued,
+   struct mpc_dma_desc, node);
+
+   /* Grab either several mem-to-mem transfer descriptors
+* or one peripheral transfer descriptor,
+* don't mix mem-to-mem and peripheral transfer descriptors
+* within the same 'active' list. */
+   if (mdesc->will_access_peripheral) {
+   if (list_empty(&mchan->active))
+   list_move_tail(&mdesc->node, &mchan->active);
+   break;
+   } else
+   list_move_tail(&mdesc->node, &mchan->active);
+   }
 
/* Chain descriptors into one transaction */
list_for_each_entry(mdesc, &mchan->active, node) {
@@ -264,6 +290,8 @@ static void mpc_dma_execute(struct mpc_dma_chan *mchan)
 
prev->tcd->dlast_sga = mdesc->tcd_paddr;
prev->tcd->e_sg = 1;
+
+   /* software initiated start for chained transfers */
mdesc->tcd->start = 1;
 
prev = mdesc;
@@ -276,7 +304,17 @@ static void mpc_dma_execute(struct mpc_dma_chan *mchan)
 
if (first != prev)
mdma->tcd[cid].e_sg = 1;
-   out_8(&mdma->regs->dmassrt, cid);
+
+   if (mdma->is_mpc8308) {
+   /* MPC8308, no request lines, software initiated start */
+   out_8(&mdma->regs->dmassrt, cid);
+   } else if (first->will_access_peripheral) {
+   /* peripherals involved, start by external request signal */
+   out_8(&mdma->regs->dmaserq, cid);
+   } else {
+   /* memory to memory transfer, software initiated start */
+   out_8(&mdma->regs->dmassrt, cid);
+   }
 }
 
 /* Handle interrupt on one half of DMA controller (32 channels) */
@@ -594,6 +632,7 @@ mpc_dma_prep_memcpy(struct dma_chan *chan, dma_addr_t dst, 
dma_addr_t src,
}
 
mdesc->error = 0;
+   mdesc->will_access_peripheral = 0;
tcd = mdesc->tcd;
 
/* Prepare Transfer Control Descr

[PATCH RFC v5 0/5] MPC512x DMA slave s/g support, OF DMA lookup

[Alexander Popov]

03.10.2013 18:00, Alexander Popov :
> v2013/7/14 Gerhard Sittig :
>> this series
>> - introduces slave s/g support (that's support for DMA transfers which
>>involve peripherals in contrast to mem-to-mem transfers)
>> - adds device tree based lookup support for DMA channels
>> - combines floating patches and related feedback which already covered
>>several aspects of what the suggested LPB driver needs, to demonstrate
>>how integration might be done
>> - carries Q&D SD card support to enable another DMA client during test,
>>while this patch needs to get dropped upon pickup
>>

Changes in v2:
>> - re-order mpc8308 related code paths for improved readability, no
>>change in behaviour, introduction of symbolic channel names here
>>already
>> - squash 'execute() start condition' and 'terminate all' into the
>>introduction of 'slave s/g prep' and 'device control' support; refuse
>>s/g lists with more than one item since slave support is operational
>>yet proper s/g support is missing (can get addressed later)
>> - always start transfers from software on MPC8308 as there are no
>>external request lines for peripheral flow control
>> - drop dt-bindings header file and symbolic channel names in OF nodes

Changes in v3 and v4:
> Part 1/5:
> - use #define instead of enum since individual channels don't require
>special handling.
> Part 2/5:
> - add a flag "will_access_peripheral" to DMA transfer descriptor
>according recommendations of Gerhard Sittig.
>This flag is set in mpc_dma_prep_memcpy() and mpc_dma_prep_slave_sg()
>and is evaluated in mpc_dma_execute() to choose a type of start for
>the transfer.
> - prevent descriptors of transfers which involve peripherals from
>being chained together;
>each of such transfers needs hardware initiated start.
> - add locking while working with struct mpc_dma_chan
>according recommendations of Lars-Peter Clausen.
> - remove default nbytes value. Client kernel modules must set
>src_maxburst and dst_maxburst fields of struct dma_slave_config 
> (dmaengine.h).

Changes in v5:
 Part 2/5::
 - add and improve comments;
 - improve the code moving transfer descriptors from 'queued' to 'active' list
in mpc_dma_execute();
 - allow mpc_dma_prep_slave_sg() to run with non-empty 'active' list;
 - take 'mdesc' back to 'free' list in case of error in mpc_dma_prep_slave_sg();
 - improve checks of the transfer parameters;
 - provide the default value for 'maxburst' in mpc_dma_device_control().

Last changes are tested on MPC5125
 - with SCLPC driver (transfers between dev and mem work fine);
 - with dmatest module (all 64 DMA channels can perform mem-to-mem transfers
which are chained correctly now).

>> known issues:
>> - it's yet to get confirmed whether MPC8308 can use slave support or
>>whether the DMA controller's driver shall actively reject it, the
>>information that's available so far suggests that peripheral transfers
>>to IP bus attached I/O is useful and shall not get blocked right away
 - adding support for transfers which don't increment the RAM address or
do increment the peripheral "port's" address is easy with
this implementation; but which options of the common API
should be used for specifying such transfers?


Alexander Popov (2):
  dma: mpc512x: reorder mpc8308 specific instructions
  dma: mpc512x: add support for peripheral transfers

Gerhard Sittig (2):
  dma: mpc512x: register for device tree channel lookup
  HACK mmc: mxcmmc: enable clocks for the MPC512x

Lars-Peter Clausen (1):
  dma: of: Add common xlate function for matching by channel id

 .../devicetree/bindings/dma/mpc512x-dma.txt|  55 
 arch/powerpc/boot/dts/mpc5121.dtsi |   1 +
 drivers/dma/mpc512x_dma.c  | 295 +++--
 drivers/dma/of-dma.c   |  47 
 drivers/mmc/host/mxcmmc.c  |  41 ++-
 include/linux/of_dma.h |   4 +
 6 files changed, 404 insertions(+), 39 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/dma/mpc512x-dma.txt

-- 
1.7.11.3

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[PATCH RFC v5 1/5] dma: mpc512x: reorder mpc8308 specific instructions

[Alexander Popov]

Concentrate the specific code for MPC8308 in the 'if' branch
and handle MPC512x in the 'else' branch.
This modification only reorders instructions but doesn't change behaviour.

Signed-off-by: Alexander Popov 
---
 drivers/dma/mpc512x_dma.c | 42 +-
 1 file changed, 25 insertions(+), 17 deletions(-)

diff --git a/drivers/dma/mpc512x_dma.c b/drivers/dma/mpc512x_dma.c
index 2fe4353..f41639f 100644
--- a/drivers/dma/mpc512x_dma.c
+++ b/drivers/dma/mpc512x_dma.c
@@ -50,9 +50,17 @@
 #define MPC_DMA_DESCRIPTORS64
 
 /* Macro definitions */
-#define MPC_DMA_CHANNELS   64
 #define MPC_DMA_TCD_OFFSET 0x1000
 
+/*
+ * Maximum channel counts for individual hardware variants
+ * and the maximum channel count over all supported controllers,
+ * used for data structure size
+ */
+#define MPC8308_DMACHAN_MAX16
+#define MPC512x_DMACHAN_MAX64
+#define MPC_DMA_CHANNELS   64
+
 /* Arbitration mode of group and channel */
 #define MPC_DMA_DMACR_EDCG (1 << 31)
 #define MPC_DMA_DMACR_ERGA (1 << 3)
@@ -708,10 +716,10 @@ static int mpc_dma_probe(struct platform_device *op)
 
dma = &mdma->dma;
dma->dev = dev;
-   if (!mdma->is_mpc8308)
-   dma->chancnt = MPC_DMA_CHANNELS;
+   if (mdma->is_mpc8308)
+   dma->chancnt = MPC8308_DMACHAN_MAX;
else
-   dma->chancnt = 16; /* MPC8308 DMA has only 16 channels */
+   dma->chancnt = MPC512x_DMACHAN_MAX;
dma->device_alloc_chan_resources = mpc_dma_alloc_chan_resources;
dma->device_free_chan_resources = mpc_dma_free_chan_resources;
dma->device_issue_pending = mpc_dma_issue_pending;
@@ -745,7 +753,19 @@ static int mpc_dma_probe(struct platform_device *op)
 * - Round-robin group arbitration,
 * - Round-robin channel arbitration.
 */
-   if (!mdma->is_mpc8308) {
+   if (mdma->is_mpc8308) {
+   /* MPC8308 has 16 channels and lacks some registers */
+   out_be32(&mdma->regs->dmacr, MPC_DMA_DMACR_ERCA);
+
+   /* enable snooping */
+   out_be32(&mdma->regs->dmagpor, MPC_DMA_DMAGPOR_SNOOP_ENABLE);
+   /* Disable error interrupts */
+   out_be32(&mdma->regs->dmaeeil, 0);
+
+   /* Clear interrupts status */
+   out_be32(&mdma->regs->dmaintl, 0x);
+   out_be32(&mdma->regs->dmaerrl, 0x);
+   } else {
out_be32(&mdma->regs->dmacr, MPC_DMA_DMACR_EDCG |
MPC_DMA_DMACR_ERGA | 
MPC_DMA_DMACR_ERCA);
 
@@ -766,18 +786,6 @@ static int mpc_dma_probe(struct platform_device *op)
/* Route interrupts to IPIC */
out_be32(&mdma->regs->dmaihsa, 0);
out_be32(&mdma->regs->dmailsa, 0);
-   } else {
-   /* MPC8308 has 16 channels and lacks some registers */
-   out_be32(&mdma->regs->dmacr, MPC_DMA_DMACR_ERCA);
-
-   /* enable snooping */
-   out_be32(&mdma->regs->dmagpor, MPC_DMA_DMAGPOR_SNOOP_ENABLE);
-   /* Disable error interrupts */
-   out_be32(&mdma->regs->dmaeeil, 0);
-
-   /* Clear interrupts status */
-   out_be32(&mdma->regs->dmaintl, 0x);
-   out_be32(&mdma->regs->dmaerrl, 0x);
}
 
/* Register DMA engine */
-- 
1.7.11.3

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[PATCH RFC v5 4/5] dma: mpc512x: register for device tree channel lookup

[Alexander Popov]

From: Gerhard Sittig 

register the controller for device tree based lookup of DMA channels
(non-fatal for backwards compatibility with older device trees), provide
the '#dma-cells' property in the shared mpc5121.dtsi file, and introduce
a bindings document for the MPC512x DMA controller

Signed-off-by: Gerhard Sittig 
---
 .../devicetree/bindings/dma/mpc512x-dma.txt| 55 ++
 arch/powerpc/boot/dts/mpc5121.dtsi |  1 +
 drivers/dma/mpc512x_dma.c  | 21 +++--
 3 files changed, 74 insertions(+), 3 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/dma/mpc512x-dma.txt

diff --git a/Documentation/devicetree/bindings/dma/mpc512x-dma.txt 
b/Documentation/devicetree/bindings/dma/mpc512x-dma.txt
new file mode 100644
index 000..a4867d5
--- /dev/null
+++ b/Documentation/devicetree/bindings/dma/mpc512x-dma.txt
@@ -0,0 +1,55 @@
+* Freescale MPC512x DMA Controller
+
+The DMA controller in the Freescale MPC512x SoC can move blocks of
+memory contents between memory and peripherals or memory to memory.
+
+Refer to the "Generic DMA Controller and DMA request bindings" description
+in the dma.txt file for a more detailled discussion of the binding.  The
+MPC512x DMA engine binding follows the common scheme, but doesn't provide
+support for the optional channels and requests counters (those values are
+derived from the detected hardware features) and has a fixed client
+specifier length of 1 integer cell (the value is the DMA channel, since
+the DMA controller uses a fixed assignment of request lines per channel).
+
+
+DMA controller node properties:
+
+Required properties:
+- compatible:  should be "fsl,mpc5121-dma"
+- reg: address and size of the DMA controller's register set
+- interrupts:  interrupt spec for the DMA controller
+
+Optional properties:
+- #dma-cells:  must be <1>, describes the number of integer cells
+   needed to specify the 'dmas' property in client nodes,
+   strongly recommended since common client helper code
+   uses this property
+
+Example:
+
+   dma0: dma@14000 {
+   compatible = "fsl,mpc5121-dma";
+   reg = <0x14000 0x1800>;
+   interrupts = <65 0x8>;
+   #dma-cells = <1>;
+   };
+
+
+Client node properties:
+
+Required properties:
+- dmas:list of DMA specifiers, consisting each of a 
handle
+   for the DMA controller and integer cells to specify
+   the channel used within the DMA controller
+- dma-names:   list of identifier strings for the DMA specifiers,
+   client device driver code uses these strings to
+   have DMA channels looked up at the controller
+
+Example:
+
+   sdhc@1500 {
+   compatible = "fsl,mpc5121-sdhc";
+   /* ... */
+   dmas = <&dma0 30>;
+   dma-names = "rx-tx";
+   };
diff --git a/arch/powerpc/boot/dts/mpc5121.dtsi 
b/arch/powerpc/boot/dts/mpc5121.dtsi
index bd14c00..eb0058f 100644
--- a/arch/powerpc/boot/dts/mpc5121.dtsi
+++ b/arch/powerpc/boot/dts/mpc5121.dtsi
@@ -390,6 +390,7 @@
compatible = "fsl,mpc5121-dma";
reg = <0x14000 0x1800>;
interrupts = <65 0x8>;
+   #dma-cells = <1>;
};
};
 
diff --git a/drivers/dma/mpc512x_dma.c b/drivers/dma/mpc512x_dma.c
index d2ec42d..9929cdc 100644
--- a/drivers/dma/mpc512x_dma.c
+++ b/drivers/dma/mpc512x_dma.c
@@ -48,6 +48,7 @@
 #include 
 #include 
 #include 
+#include 
 #include 
 
 #include 
@@ -1013,11 +1014,23 @@ static int mpc_dma_probe(struct platform_device *op)
/* Register DMA engine */
dev_set_drvdata(dev, mdma);
retval = dma_async_device_register(dma);
-   if (retval) {
-   devm_free_irq(dev, mdma->irq, mdma);
-   irq_dispose_mapping(mdma->irq);
+   if (retval)
+   goto out_irq;
+
+   /* register with OF helpers for DMA lookups (nonfatal) */
+   if (dev->of_node) {
+   retval = of_dma_controller_register(dev->of_node,
+   of_dma_xlate_by_chan_id,
+   mdma);
+   if (retval)
+   dev_warn(dev, "could not register for OF lookup\n");
}
 
+   return 0;
+
+out_irq:
+   devm_free_irq(dev, mdma->irq, mdma);
+   irq_dispose_mapping(mdma->irq);
return retval;
 }
 
@@ -1026,6 +1039,8 @@ static int mpc_dma_remove(struct platform_device *op)
struct device *dev = &op->dev;
struct mpc_dma *mdma = dev_get_drvdata(dev);
 
+   if (dev->of_node)
+   of_dma_controller_free(dev->of_node);
dma_async_device_unregister(&mdma->dma);
devm_free_ir

[PATCH RFC v5 3/5] dma: of: Add common xlate function for matching by channel id

[Alexander Popov]

From: Lars-Peter Clausen 

This patch adds a new common OF dma xlate callback function which will match a
channel by it's id. The binding expects one integer argument which it will use 
to
lookup the channel by the id.

Unlike of_dma_simple_xlate this function is able to handle a system with
multiple DMA controllers. When registering the of dma provider with
of_dma_controller_register a pointer to the dma_device struct which is
associated with the dt node needs to passed as the data parameter. The filter
function will use this pointer to match only channels which belong to the
specified DMA controller.

Signed-off-by: Lars-Peter Clausen 
Signed-off-by: Gerhard Sittig 
---
 drivers/dma/of-dma.c   | 47 +++
 include/linux/of_dma.h |  4 
 2 files changed, 51 insertions(+)

diff --git a/drivers/dma/of-dma.c b/drivers/dma/of-dma.c
index 0b88dd3..aa9c425 100644
--- a/drivers/dma/of-dma.c
+++ b/drivers/dma/of-dma.c
@@ -215,3 +215,50 @@ struct dma_chan *of_dma_simple_xlate(struct 
of_phandle_args *dma_spec,
&dma_spec->args[0]);
 }
 EXPORT_SYMBOL_GPL(of_dma_simple_xlate);
+
+struct of_dma_filter_by_chan_id_args {
+   struct dma_device *dev;
+   unsigned int chan_id;
+};
+
+static bool of_dma_filter_by_chan_id(struct dma_chan *chan, void *params)
+{
+   struct of_dma_filter_by_chan_id_args *args = params;
+
+   return chan->device == args->dev && chan->chan_id == args->chan_id;
+}
+
+/**
+ * of_dma_xlate_by_chan_id - Translate dt property to DMA channel by channel id
+ * @dma_spec:  pointer to DMA specifier as found in the device tree
+ * @of_dma:pointer to DMA controller data
+ *
+ * This function can be used as the of xlate callback for DMA driver which 
wants
+ * to match the channel based on the channel id. When using this xlate function
+ * the #dma-cells propety of the DMA controller dt node needs to be set to 1.
+ * The data parameter of of_dma_controller_register must be a pointer to the
+ * dma_device struct the function should match upon.
+ *
+ * Returns pointer to appropriate dma channel on success or NULL on error.
+ */
+struct dma_chan *of_dma_xlate_by_chan_id(struct of_phandle_args *dma_spec,
+struct of_dma *ofdma)
+{
+   struct of_dma_filter_by_chan_id_args args;
+   dma_cap_mask_t cap;
+
+   args.dev = ofdma->of_dma_data;
+   if (!args.dev)
+   return NULL;
+
+   if (dma_spec->args_count != 1)
+   return NULL;
+
+   dma_cap_zero(cap);
+   dma_cap_set(DMA_SLAVE, cap);
+
+   args.chan_id = dma_spec->args[0];
+
+   return dma_request_channel(cap, of_dma_filter_by_chan_id, &args);
+}
+EXPORT_SYMBOL_GPL(of_dma_xlate_by_chan_id);
diff --git a/include/linux/of_dma.h b/include/linux/of_dma.h
index ae36298..56bc026 100644
--- a/include/linux/of_dma.h
+++ b/include/linux/of_dma.h
@@ -41,6 +41,8 @@ extern struct dma_chan *of_dma_request_slave_channel(struct 
device_node *np,
 const char *name);
 extern struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_spec,
struct of_dma *ofdma);
+extern struct dma_chan *of_dma_xlate_by_chan_id(struct of_phandle_args 
*dma_spec,
+   struct of_dma *ofdma);
 #else
 static inline int of_dma_controller_register(struct device_node *np,
struct dma_chan *(*of_dma_xlate)
@@ -66,6 +68,8 @@ static inline struct dma_chan *of_dma_simple_xlate(struct 
of_phandle_args *dma_s
return NULL;
 }
 
+#define of_dma_xlate_by_chan_id NULL
+
 #endif
 
 #endif /* __LINUX_OF_DMA_H */
-- 
1.7.11.3

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[PATCH RFC v5 5/5] HACK mmc: mxcmmc: enable clocks for the MPC512x

[Alexander Popov]

From: Gerhard Sittig 

Q&D HACK to enable SD card support without correct COMMON_CLK support,
best viewed with 'git diff -w -b', NOT acceptable for mainline (NAKed)

Signed-off-by: Gerhard Sittig 
---
 drivers/mmc/host/mxcmmc.c | 41 +++--
 1 file changed, 27 insertions(+), 14 deletions(-)

diff --git a/drivers/mmc/host/mxcmmc.c b/drivers/mmc/host/mxcmmc.c
index c174c6a..ae13bc9 100644
--- a/drivers/mmc/host/mxcmmc.c
+++ b/drivers/mmc/host/mxcmmc.c
@@ -1123,20 +1123,29 @@ static int mxcmci_probe(struct platform_device *pdev)
host->res = r;
host->irq = irq;
 
-   host->clk_ipg = devm_clk_get(&pdev->dev, "ipg");
-   if (IS_ERR(host->clk_ipg)) {
-   ret = PTR_ERR(host->clk_ipg);
-   goto out_iounmap;
-   }
+   if (!is_mpc512x_mmc(host)) {
+   host->clk_ipg = devm_clk_get(&pdev->dev, "ipg");
+   if (IS_ERR(host->clk_ipg)) {
+   ret = PTR_ERR(host->clk_ipg);
+   goto out_iounmap;
+   }
 
-   host->clk_per = devm_clk_get(&pdev->dev, "per");
-   if (IS_ERR(host->clk_per)) {
-   ret = PTR_ERR(host->clk_per);
-   goto out_iounmap;
+   host->clk_per = devm_clk_get(&pdev->dev, "per");
+   if (IS_ERR(host->clk_per)) {
+   ret = PTR_ERR(host->clk_per);
+   goto out_iounmap;
+   }
+   } else {
+   host->clk_per = devm_clk_get(&pdev->dev, "sdhc_clk");
+   if (IS_ERR(host->clk_per)) {
+   ret = PTR_ERR(host->clk_per);
+   goto out_iounmap;
+   }
}
 
clk_prepare_enable(host->clk_per);
-   clk_prepare_enable(host->clk_ipg);
+   if (host->clk_ipg)
+   clk_prepare_enable(host->clk_ipg);
 
mxcmci_softreset(host);
 
@@ -1206,7 +1215,8 @@ out_free_dma:
dma_release_channel(host->dma);
 out_clk_put:
clk_disable_unprepare(host->clk_per);
-   clk_disable_unprepare(host->clk_ipg);
+   if (host->clk_ipg)
+   clk_disable_unprepare(host->clk_ipg);
 out_iounmap:
iounmap(host->base);
 out_free:
@@ -1236,7 +1246,8 @@ static int mxcmci_remove(struct platform_device *pdev)
dma_release_channel(host->dma);
 
clk_disable_unprepare(host->clk_per);
-   clk_disable_unprepare(host->clk_ipg);
+   if (host->clk_ipg)
+   clk_disable_unprepare(host->clk_ipg);
 
release_mem_region(host->res->start, resource_size(host->res));
 
@@ -1255,7 +1266,8 @@ static int mxcmci_suspend(struct device *dev)
if (mmc)
ret = mmc_suspend_host(mmc);
clk_disable_unprepare(host->clk_per);
-   clk_disable_unprepare(host->clk_ipg);
+   if (host->clk_ipg)
+   clk_disable_unprepare(host->clk_ipg);
 
return ret;
 }
@@ -1267,7 +1279,8 @@ static int mxcmci_resume(struct device *dev)
int ret = 0;
 
clk_prepare_enable(host->clk_per);
-   clk_prepare_enable(host->clk_ipg);
+   if (host->clk_ipg)
+   clk_prepare_enable(host->clk_ipg);
if (mmc)
ret = mmc_resume_host(mmc);
 
-- 
1.7.11.3

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